Dark Chocolate Mousse Cake

This super moist dark chocolate mousse cake combines unsweetened natural cocoa powder and dark cocoa powder for an extra rich flavor. Fill the cake with a simplified chocolate mousse and cover the whole dessert with semi-sweet chocolate ganache. If needed, you can prepare the ganache and mousse ahead of time.

slice of dark chocolate mousse cake on a cake server

Chocolate mousse is simple divinity in its own right, but when paired with chocolate cake, it’s downright decadent. And then add chocolate ganache to the mix? Have mercy.

This spectacularly rich chocolate cake is such a personal and reader favorite that I knew I had to include it in my cookbook, Sally’s Baking 101 (which has become a New York Times Best Seller!). The cakes chapter just would not have been complete without it!

It’s actually the first recipe in that chapter, and in the book it’s titled “Chocolate Ganache Cake: 2 Ways,” because I include a second filling option—peanut butter frosting instead of chocolate mousse, just like this recipe for dark chocolate peanut butter cake. Both versions of ganache-topped chocolate layer cakes have received such glowing reviews on my website, I simply couldn’t choose between them… so I found a way to include them both!


This cake basically demands a huge gathering because—trust me—you don’t want to be left alone with its temptation. It WILL call out your name each time you open the refrigerator.

Taunting you.

One reader, Judy, commented:Don’t make this cake unless you want everyone who has a bite to request that you make it for every special occasion for the rest of time 🙂 I do four layers and follow the recipe exactly, and it has come out perfectly every time. I’ve already made at least ten of these cakes. Fabulous! ★★★★★

One reader, Cecilia, commented:OMG! This cake is absolutely divine! It’s a chocolate lover’s dream. The chocolate mousse is heavenly. I made it for my niece’s birthday and ended up making a four-layer cake. There were no leftovers. I don’t need any other chocolate cake recipe. This is it! Definitely the best! ★★★★★

One reader, Brittney, commented:This cake turned out amazing! I made it for a birthday party… and it was requested to be the new ‘party cake’! ★★★★★

chocolate layer cake on a wooden cake stand

3 Parts to Dark Chocolate Mousse Cake

Let’s break down each component of this intensely rich cake:

  1. Dark Chocolate Cake: This is actually a variation of my tuxedo cake, which originated from my chocolate cake recipe. In recent years, I’ve found that replacing sour cream for some of the buttermilk gives the cake more structure.
  2. Chocolate Mousse: I researched simplified ways to make a fluffy chocolate mousse filling without the use of eggs or gelatin. This chocolate mousse filling combines real chocolate and homemade whipped cream. Or our whipped frosting would make a wonderful alternative filling if you don’t want to make the chocolate mousse!
  3. Chocolate Ganache: Top the whole cake with 2 ingredient semi-sweet chocolate ganache. You should be a chocolate ganache pro by now!

Video Tutorial: Chocolate Mousse Cake

Stick-to-the-back-of-your-fork moist. This is every chocolate lover’s dream!

4 layer chocolate cake

Dark Chocolate Cake

Use this chocolate cake as the starting point. For a sturdier, yet moister crumb, swap some sour cream in for the buttermilk and reduce the hot liquid. The acidity in both sour cream and buttermilk is a must to properly leaven this cake. (If desired, see my posts on Baking Powder vs Baking Soda and Baking with Buttermilk for more information.) This cake has a natural dark chocolate taste, but to deepen that flavor, use a mix of natural cocoa and Hershey’s Special Dark cocoa powder. A touch of espresso powder and hot coffee further enhances the chocolate flavor. The cake will not taste like coffee. Rather, the two add depth to the cake’s chocolate flavor.

  • Why hot liquid? The hot liquid encourages the cocoa powder to bloom and dissolve. If you don’t drink coffee, you can use hot water.

You have options! You can make this cake into 2, 3, or 4 layers. I highly recommend 3 or 4 layers because there’s over 4 cups of chocolate mousse to spread inside. You can use 8 inch or 9 inch pans. The bake times are similar, see recipe notes.

A cup of chocolate chips adds even more chocolate flavor. I used 1 cup (180g) of mini semi-sweet chocolate chips in this pictured cake, but left them out in the video. They’re optional, but definitely worth the addition!!

You can also see this exact cake batter baked as three layers in both my chocolate peanut butter cake and chocolate raspberry cake (try one of those next!).

chocolate cake batter in glass bowl

Simplified Chocolate Mousse

The chocolate mousse adds a creamy and light contrast to the dark chocolate layers. You need 6 ingredients:

  1. Hot Water
  2. Cocoa Powdernatural or dutch-process
  3. Melted Chocolateuse two 4-ounce chocolate baking bars found in the baking aisle
  4. Heavy Cream
  5. Confectioners’ Sugar
  6. Vanilla Extract

Whisk the hot water and cocoa powder together. Pour into melted chocolate. The hot water breaks up the chocolate, adding to the airy mousse consistency. Cocoa powder creates additional chocolate flavor. Fold this chocolate mixture into whipped cream—a combination of heavy cream, confectioners’ sugar, and vanilla extract.

2 images of making chocolate mousse including whipped cream and chocolate mixture in glass bowls

Whipped cream + our chocolate mixture. ↑

Fold them together to make our chocolate mousse filling. ↓

chocolate mousse for chocolate cake in glass bowl and between cake layers

Baker’s Tip: The chocolate mousse must chill in the refrigerator before using, so it’s a good idea to make it ahead of time or as the chocolate cake layers are cooling. The mousse is best cold, so I actually recommend serving the cake cold. (Additionally, the cake is much easier to assemble if the mousse is cold!)

By the way, this chocolate mousse also makes for a wonderful alternate filling in homemade eclairs!

2 images of chocolate ganache in glass bowl and pouring on chocolate cake

Chocolate Ganache

I won’t go into a lot of detail about the chocolate ganache because I have a complete chocolate ganache tutorial for you! Like the chocolate mousse, it’s imperative to use pure chocolate. Wait about 20 minutes for the ganache to thicken before pouring onto the cake.

How to Assemble & Decorate Chocolate Mousse Cake

Chocolate ganache enrobes 4 cake layers and 3 mousse layers. Place bottom cake layer on your cake stand or serving plate. Using a large icing spatula, evenly cover the top with about 1.5 cups of chilled chocolate mousse. Top with 2nd cake layer and another 1.5 cups of mousse. Top with the third cake layer, then spread another 1.5 cups mousse evenly on top. (Save a large spoonful of mousse for a thin crumb coat.) Top with final 4th cake layer. Spread any remaining mousse around the sides as a crumb coat. Run a bench scraper around the cake to smooth it out. Refrigerate cake for at least 1 hour and up to 4 hours. Chocolate mousse is pretty fluffy, so the cake won’t hold its shape unless it’s properly chilled.

Pour ganache on top then run a bench scraper around the sides to smooth it out. You can serve the cake immediately or wait for the chocolate ganache to set. 🙂

top of chocolate mousse cake with berries and chocolate shavings
slice of chocolate mousse cake on a white plate

What About Cupcakes?

Instead of a big cake, you can make chocolate mousse cupcakes. Use my chocolate cupcakes recipe and halve the chocolate mousse and chocolate ganache recipes below. Fill the cupcakes with chocolate mousse using my Sugar Plum Fairy Cupcakes as an example. Drizzle cooled cupcakes with ganache. Eat your heart out!

You can also use the chocolate mousse instead of pastry cream in homemade mille-feuille!

More Indulgent Chocolate Desserts

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4 layer chocolate cake

Dark Chocolate Mousse Cake

5 Stars 4 Stars 3 Stars 2 Stars 1 Star 4.9 from 403 reviews
  • Author: Sally McKenney
  • Prep Time: 2 hours, 30 minutes (includes chilling)
  • Cook Time: 25 minutes
  • Total Time: 5 hours, 55 minutes (includes cooling)
  • Yield: serves 12
  • Category: Cake
  • Method: Baking
  • Cuisine: American
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Description

This super moist dark chocolate cake combines unsweetened natural cocoa powder and dark cocoa powder for an extra rich flavor. Fill the cake with a simplified chocolate mousse and cover it with semi-sweet chocolate ganache. If needed, you can prepare the ganache and mousse ahead of time (see Notes). This recipe is also in my New York Times best-selling cookbook, Sally’s Baking 101.


Ingredients

  • 1 and 3/4 cups (219g) all-purpose flour (spooned & leveled)
  • 1 and 3/4 cups (350g) granulated sugar
  • 3/4 cup (64g) unsweetened natural cocoa powder* (see Notes)
  • 2 teaspoons espresso powder (optional)*
  • 2 teaspoons baking soda
  • 1 teaspoon baking powder
  • 1 teaspoon salt
  • 3/4 cup (180g) full-fat sour cream, at room temperature
  • 1/2 cup (113g/120ml) vegetable oil
  • 2 large eggs, at room temperature
  • 1/2 cup (120g/ml) buttermilk, at room temperature*
  • 2 teaspoons pure vanilla extract
  • 1/2 cup (120g/ml) hot water or black coffee*
  • 1 cup (170g) semi-sweet mini chocolate chips tossed in 1 Tbsp flour (optional)

Chocolate Mousse

  • 1/2 cup (120g/ml) hot water
  • 1/4 cup (21g) unsweetened natural or Dutch-process cocoa powder
  • 8 ounces (226g) quality semi-sweet chocolate, finely chopped*
  • 2 cups (480g/ml) heavy cream, cold
  • 2 Tablespoons confectioners’ sugar
  • 1/2 teaspoon pure vanilla extract

Chocolate Ganache

  • 8 ounces (226g) quality semi-sweet chocolate, finely chopped
  • 1 cup (240g/ml) heavy cream
  • optional, for garnish: fresh berries and/or chocolate shavings


Instructions

  1. Preheat the oven to 350°F (177°C). Grease four 8-inch or 9-inch cake pans, line with parchment paper rounds, then grease the parchment paper. Parchment paper helps the cakes seamlessly release from the pans. (If it’s helpful, see this parchment paper rounds for cakes video & post.)
  2. Make the cake: In a large bowl, whisk the flour, sugar, cocoa powder, espresso powder, baking soda, baking powder, and salt together. Set aside.
  3. In another large bowl using a handheld or stand mixer fitted with a whisk attachment (or you can use a whisk) mix the sour cream, oil, and eggs together on medium-high speed until combined. Add the buttermilk and vanilla and mix until combined. Pour the dry ingredients into the wet ingredients, add the hot water/coffee, and whisk or beat on low speed until combined. Fold in the floured mini chocolate chips, if using. Divide the batter evenly among the prepared pans.
  4. Bake for 19–23 minutes. Baking times vary, so keep an eye on yours. The cakes are done when a toothpick inserted in the center comes out clean. Cool the cakes in the pans set on a cooling rack for 1 hour. Run a knife around the edges to help loosen the sides, remove the cakes from the pans, peel off the parchment, and place on the rack to finish cooling. The cakes may slightly sink in the middle as they cool—that’s expected.
  5. Make the chocolate mousse: In a small bowl, whisk the hot water and cocoa powder together until smooth. Melt the chopped chocolate in a double boiler or use the microwave. If using the microwave: place the chopped chocolate in a medium heat-proof bowl. Microwave for 20-second increments, stirring after each increment until completely melted and smooth. Pour hot water/cocoa mixture into the melted chocolate and stir until thick and smooth. Set aside. In a large bowl using a handheld or stand mixer fitted with a whisk attachment, whip the heavy cream, confectioners’ sugar, and vanilla extract together on medium-high speed until medium peaks form, about 3 minutes. Medium peaks are between soft/loose peaks and stiff peaks. Pour in the chocolate mixture and gently fold together with a spatula. Do not overmix, as this could deflate it. Cover the mousse and refrigerate for at least 2 hours or up to 2 days. Makes about 4.5 cups (about 900g).
  6. Assemble the cake before preparing chocolate ganache: First, level the cakes (if needed): using a large serrated knife, slice a thin layer off the tops of the cakes to create a flat surface. Place 1 cake layer on your cake stand, cake turntable, or serving plate. Using a large icing spatula, evenly cover the top with about 1.5 cups (200g) of chocolate mousse. Top with the second layer, upside down, and evenly cover the top with the same amount of chocolate mousse. Top with the third cake layer, right side up, and again cover with the same amount of mousse. Top with final cake layer. Spread the remaining mousse on top and around the sides of the cake as a crumb coat. Run a bench scraper around the cake to smooth out the sides. Refrigerate for at least 1 hour and up to 4 hours. Prepare the ganache while the cake is chilling. 
  7. Make the chocolate ganache: Place the chocolate in a medium heat-proof bowl. In a small saucepan, heat the cream over medium heat just until it begins to gently simmer. (Do not let it come to a rapid boil—that’s too hot!) Pour the warm cream over the chocolate and let it sit for 2–3 minutes to gently soften the chocolate. With a metal spoon or small spatula, slowly stir until the chocolate has melted and the mixture is smooth. The finer you chopped the chocolate, the quicker it will melt with the cream. If it’s not melting, do not microwave it. If needed, see Troubleshooting Chocolate Ganache. Refrigerate the ganache for at least 30 minutes or up to 1 hour to thicken.
  8. Pour/spoon the thickened ganache on the chilled cake. Smooth the top and sides with an icing spatula. Top with optional garnish such as fresh berries and/or chocolate shavings. Serve cake immediately or chill, uncovered, for up to 4–6 hours before serving. Cake can be served at room temperature or chilled.
  9. Cover leftover cake tightly and store in the refrigerator for up to 5 days.

Notes

  1. Make Ahead & Freezing Instructions: Prepare cake through step 4. Wrap the individual baked and cooled cake layers tightly and refrigerate for up to 2 days or freeze up to 3 months. Bring to room temperature, make mousse filling, then continue with step 6. You can prepare the chocolate mousse in advance. See step 5. You can also prepare the chocolate ganache ahead of time too. Refrigerate prepared ganache for up to 3 days. Bring to room temperature before spreading onto cake. You can freeze cake for up to 3 months. Thaw overnight in the refrigerator, then bring to room temperature or serve cold. See How to Freeze Cakes for more information.
  2. Special Tools (affiliate links): 8-inch Round Cake Pans or 9-inch Round Cake Pans | Glass Mixing Bowl | Whisk | Electric Mixer (Handheld or Stand) | Cooling Rack | Double Boiler | Cake Stand or Cake Turntable | Large Icing Spatula | Bench Scraper | Cake Carrier (for storage)
  3. 3-Layer Cake: You can also prepare this as a 3-layer cake. Divide batter between three 8-inch or 9-inch cake pans in step 1 and bake for 24–26 minutes or until a toothpick inserted in the center comes out clean. Use about 2 cups of chocolate mousse between each layer.
  4. Espresso Powder/Coffee: Espresso powder and coffee will not make the cake taste like coffee. Rather, they deepen the chocolate flavor. I highly recommend them both. You can find espresso powder in the baking aisle at many grocery stores or online. If coffee isn’t your thing, you can leave out the espresso powder and use hot water instead of the hot coffee.
  5. Cocoa Powder: For the best dark chocolate flavor in the cake, I recommend using a blend of unsweetened natural cocoa powder (1/4 cup; 21g) and Hershey’s “Special Dark” cocoa powder (1/2 cup; 43g). Hershey’s Special Dark is actually a mix of natural cocoa powder (an acid) and Dutch-process cocoa powder (a base) and it worked fine in this recipe. This recipe needs acidic natural cocoa powder, so do not use ALL Dutch-process cocoa powder. For best results, use 3/4 cup (64g) natural or the blend of natural/Special Dark I used. For the chocolate mousse, you can use either unsweetened natural or Dutch-process cocoa powder (or the Hershey’s Special Dark).
  6. Why Room Temperature? All refrigerated items should be at room temperature so the batter mixes together easily and evenly. Read more about why room-temperature ingredients are important. Instead of sour cream, you can use plain yogurt. The cake won’t taste as rich, but it’s a fine substitute.
  7. Buttermilk: Buttermilk is required for this recipe. You can make your own DIY buttermilk substitute if needed. Add 1 teaspoon of white vinegar or lemon juice to a liquid measuring cup. Then add enough whole milk to the same measuring cup until it reaches 1/2 cup. (In a pinch, lower-fat or nondairy milks work for this soured milk, but the cake won’t taste as moist or rich.) Stir it around and let sit for 5 minutes. The homemade “buttermilk” will be somewhat curdled and ready to use in the recipe.
  8. Chocolate in Mousse & Ganache: Mousse & ganache will only set if the correct chocolate is used. You can use high-quality chocolate chips if needed (I prefer Ghirardelli semi-sweet chocolate chips), but I recommend using pure chocolate baking bars. You can find them right next to the chocolate chips in the baking aisle. They are sold in 4-ounce (113g) bars. I like Baker’s or Ghirardelli brands.
sally mckenney headshot purple shirt.
About the Author

Sally McKenney

Sally McKenney is a baker, food photographer, and New York Times best-selling author. Her kitchen-tested recipes and step-by-step tutorials have given millions of readers the knowledge and confidence to bake from scratch. Sally’s work has been featured on TODAY, Good Morning America, Taste of Home, People, and more.

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Reader Comments and Reviews

  1. Beth says:
    October 3, 2024

    Hi Sally, just wondering if you’ve tried this cake with gluten free flour?

    Thank so much!

    Reply
    1. Lexi @ Sally's Baking says:
      October 3, 2024

      Hi Beth, we haven’t personally tested it, but a few readers have reported success using a 1:1 gluten free flour blend. Let us know if you try it!

      Reply
  2. Cara says:
    September 29, 2024

    Sally’s recipes never fail me! I made this cake for my Aunt’s birthday and was told it might be the best chocolate cake ever! It was SO good! Chocolatey but not overly rich or overly sweet. The recipe was easy to follow and didn’t take long aside from cooling time. Will definitely be making again!

    Reply
  3. Susan White says:
    September 25, 2024

    Wonderful family birthday favorite! Special Dark/cocoa blend is great. I omit chocolate chips but melt a mixture of chocolates, spread thin, chill, then break into little chunks for a garnish, along with the berries.

    Reply
  4. Mary says:
    September 23, 2024

    Hi Sally!! Do you think I could add a bit of cream of tartar to the chocolate mousse so it can keep it shape better? I want to make this cake for my boyfriend birthdays and I sometimes feel that chocolate mousse based with whipped cream tends to turned runny after a day or two in the fridge.

    Reply
    1. Lexi @ Sally's Baking says:
      September 23, 2024

      Hi Mary, we haven’t found that necessary with this mousse, but you can certainly feel free to give it a try. Hope the cake is a hit!

      Reply
  5. Sandie says:
    September 22, 2024

    I am planning on making this cake for my son in-law’s birthday. To decorate the cake I was going to use chocolate curls. I see you have used chocolate shavings and I am assuming you just use a vegetable peeler to do that? Do you have something posted on making a more defined chocolate curl – I can’t see anything? Also, if I wanted to add chocolate drips can I do that by applying a second layer of a smaller amount of chocolate ganache or is the ganache too soft? Thanks 🙂

    Reply
    1. Lexi @ Sally's Baking says:
      September 23, 2024

      Hi Sandie, yes, you can definitely use chocolate curls instead. We simply use a vegetable peeler and run it down the edges of a Hershey’s chocolate bar. You can see us do it in the video tutorial from this peanut butter banana cream pie post. We haven’t tried adding a chocolate drip on top of the ganache layer, but as long as the layer around that cake has set completely, doing a drip should work. Hope the cake is a hit!

      Reply
  6. Julieann says:
    September 21, 2024

    I will be making this cake for the first time next week. I’m concerned that the amount of mousse used between the layers is exactly the same amount as the recipe makes. Will there be enough mousse?

    Reply
    1. Lexi @ Sally's Baking says:
      September 23, 2024

      Hi Julieann, yes, the mousse as written will be enough for the cake. Hope you enjoy it!

      Reply
  7. Samantha says:
    September 20, 2024

    DO NOT add chocolate chips. They ruin the cake. They are like little stones of bad chocolate in a moist cake. It will s a strange afterthought that look like it will add more flavor. Just adds bad texture

    Reply
    1. Lexi @ Sally's Baking says:
      September 20, 2024

      Hi Samantha, thank you so much for giving this recipe a try. Were your chocolate chips expired by chance? They should add to the chocolate flavor. That said, if you don’t care for the added texture, you can certainly leave them out if you wish to try this cake again. Thanks for giving it a go!

      Reply
  8. dame friandise says:
    September 15, 2024

    Oh, yum! This is an excellent recipe. I opted to do a three-tier 8″ and it came out perfect! Will make this again soon. Thanks 🙂

    Reply
  9. Susan says:
    September 15, 2024

    Delicious! Huge hit with friends & neighbors!

    Reply
  10. Lane says:
    September 15, 2024

    Hi! I want to try this recipe but only have 2 8” cake pans. Could I split the batter and have 2 thick layers? If so how long should it bake?

    Reply
    1. Michelle @ Sally's Baking says:
      September 15, 2024

      Hi Lane, you can bake half of the batter in 2 pans and bake the next 2 after.

      Reply
  11. Antoni says:
    September 8, 2024

    Hi! I am thinking of using your chocolate mousse recipe to fill a vanilla cake and frost it with buttercream. Would the cake need to be refrigerated overnight or can it sit out at room temp? Thanks!!

    Reply
    1. Lexi @ Sally's Baking says:
      September 9, 2024

      Hi Antoni, with the mousse, we’d recommend refrigerating overnight. Enjoy!

      Reply
  12. Shannon says:
    September 3, 2024

    Hi there,
    This cake looks so delicious. My sister is having twins, and her birthday is right after her due date, so I’m making her birthday cake, and she requested this one. She lives about an hour away. Do you think this cake would travel ok?

    Reply
    1. Lexi @ Sally's Baking says:
      September 3, 2024

      Hi Shannon, as long as the cake has been sufficiently chilled before traveling, that should work just fine. Hope it’s a hit!

      Reply
  13. Beth says:
    September 2, 2024

    If you want an absolutely divine, heavenly, exquisite, gourmet cake, then this Dark Chocolate Mousse Cake is for you! I make this cake for special occasions and it’s a hit every single time. The only problem is, the mousse and ganache taste SO GOOD by themselves, that I keep sampling them, hoping I’ll have enough left over for the cake!

    Reply
  14. deepthi says:
    September 1, 2024

    Can this cake be fully frosted and refrigerated the previous day before serving? Will it turn hard? can i serve it directly from
    the fridge or should it come to room temperature? please help with your reply

    Reply
    1. Sally @ Sally's Baking says:
      September 2, 2024

      Yes. Refrigerate it overnight, and then, for best taste and texture, I would let it sit at room temperature for about 1 hour before serving.

      Reply
  15. Janet says:
    August 31, 2024

    Can I use chocolate buttercream icing instead of chocolate ganache?

    Reply
    1. Sally @ Sally's Baking says:
      August 31, 2024

      Hi Janet, yes, but the cake will be much sweeter. I recommend ganache for best results.

      Reply
  16. Paul Henry says:
    August 28, 2024

    Hi Sally, what would be the recommended baking time and temperature if using 6” round baking pans

    Reply
    1. Lexi @ Sally's Baking says:
      August 28, 2024

      Hi Paul, For a 6-inch cake, we’d recommend using this chocolate cupcakes recipe as the batter to make a 3 layer 6 inch cake. See our 6 inch cake recipes post as a guide. Halve the chocolate mousse and ganache from this recipe so there’s just enough. Hope this helps!

      Reply
  17. Pam says:
    August 27, 2024

    Sally, I prepared the cake, three 10” layers. I have the buttercream in the fridge. It’s creamy but I know it will firm up in the fridge. The mousse is very light. How does the mousse as layer filling support the weight of the cake? I’m concerned I’ll make a mess and have to assemble this Thursday morning for a 60th birthday!!! Help!

    Reply
    1. Lexi @ Sally's Baking says:
      August 28, 2024

      Hi Pam, you’ll want to bring the ganache coating to room temperature before attempting to spread on the cake. The mousse holds up the cake well in this recipe on its own, but feel free to use cake dowels for extra support if you wish!

      Reply
      1. Pam says:
        August 30, 2024

        Thanks! It went quite well.

  18. Judy says:
    August 26, 2024

    DON’T make this cake unless you want everyone who has a bite request that you make it for every special occasion for the rest of time:) I do FOUR layers and follow the recipe exactly and it has come out perfectly every time and I’ve already made at least 10 of these cakes. FABULOUS!!

    Reply
  19. Cecilia says:
    August 25, 2024

    OMG! This cake is absolutely divine! It’s a chocolate lover’s dream. The chocolate mousse is heavenly. I made it for my niece’s bday and ended up making a four-layer cake. There were no leftovers. I don’t need any other chocolate cake recipe. This is it! Definitely the best! Thank you for sharing!

    Reply
  20. Suzzanne Horak says:
    August 23, 2024

    This is a great recipe! So delicious. My husband doesn’t really eat sweets, except chocolate chip cookies, and he ate a whole piece by himself! That says it all! It’s easy, just time consuming. I will definitely make this again!

    Reply
  21. Kelsey says:
    August 23, 2024

    Looking to make my step-dad a chocolate cake for his birthday and think this is the winner! He loves chocolate cake and mousse. However, I’m thinking of coating the outside with chocolate buttercream instead of chocolate ganache (we are big fans of icing in this house) – would that still give enough structure? Also concerned it might be overly sweet…what do you think?

    Reply
    1. Sally @ Sally's Baking says:
      August 23, 2024

      Hi Kelsey, it will certainly be sweet, but I think it will still be wonderful. Especially since the chocolate mousse filling isn’t overly sweet. The cake will still have enough structure and be stable when layered and complete.

      Reply
  22. CG says:
    August 22, 2024

    What can I use instead of sour cream, heavy cream and the buttermilk for a non-dairy version?

    Reply
    1. Lexi @ Sally's Baking says:
      August 22, 2024

      Hi CG, we haven’t tested a dairy-free version of this recipe, but let us know if you do any experimenting.

      Reply
  23. Megan Gschwind says:
    August 21, 2024

    Hi Sally! First wanted to say I absolutely love this recipe. It is a favorite in my family now and constantly requested for birthdays! My brother asked if I could make it for his big 30th birthday this weekend, but I would need to double it and so I’m thinking of doing it in a 13×9 sheet cake pan. Any advice on cook time and all of that would be greatly appreciated. Thanks!

    Reply
    1. Erin @ Sally's Baking says:
      August 21, 2024

      Hi Megan, you can make this recipe as a 9×13-inch sheet cake (same oven temperature, about 35-40 minutes bake time). We’re so glad this cake is a hit with your family!

      Reply
  24. Katarina says:
    August 21, 2024

    Hi Sally, just wanted to thank you for this recipe, since I first made it years ago, it’s still every family members request that I make one for each of their birthdays!! We all love the intense chocolate flavour, but not too sweet with the simple ganache, and mousse. I feel like a professional baker when I create this cake in my kitchen – I omit the chips, but otherwise follow your recipe and it never lets me down! For anyone wanting to try, I highly recommend this cake recipe to satisfy any chocolate lovers dream!

    Reply
  25. Marina says:
    August 20, 2024

    Hi, I made this last week and it was delicious! The only thing me & my family found too intense in flavour was the addition of the chocolate ganache. I am planning to make this cake again next week for my son’s birthday party however I’m concerned about it going very soft if I don’t add the ganache on the outside. Do you think just coating the cake with chocolate mousse on the outside will be enough to give the cake stability? I need to transport the cake in the car to the party (about 10min) and worried that the cake layers might ‘slide’ as the mousse goes quite soft when left out. I will refrigerate the cake as soon as we get to the party and plan on serving it chilled.
    Thank you for a wonderful and easy to follow recipe!

    Reply
    1. Lexi @ Sally's Baking says:
      August 20, 2024

      Hi Marina, a few readers have reported success doing so! You may wish to use cake dowels for extra support. Glad the cake was a hit!

      Reply
  26. Ginny says:
    August 17, 2024

    Hi Sally, can I bake this on a sheet pan? What should be the temperature setting and baking time? I love your recipes

    Reply
    1. Michelle @ Sally's Baking says:
      August 18, 2024

      Hi Ginny, You can make this recipe as a 9×13-inch sheet cake (same oven temperature, about 35-40 minutes bake time).

      Reply
  27. Marina says:
    August 15, 2024

    Hi Sally, I like in UK and we don’t seem to have semi-sweet chocolate.. could I replace this with milk chocolate or 50/50 milk/dark?
    Also, could I use self raising flour instead of plain flour?
    Thank you!

    Reply
    1. Lexi @ Sally's Baking says:
      August 15, 2024

      Hi Marina, yes, you could use milk chocolate or 50/50—just be sure that they are still pure baking chocolate bars. We do not recommend self raising flour here, since they have varying amount of leavening in them. Best to use all-purpose here. Hope you enjoy the cake!

      Reply
  28. SherriM says:
    August 15, 2024

    I was trying to figure out if the chocolate mixture needs to sit to cool before adding the whipped cream for the mousse. I would think if still hot it would just melt the whipped cream, so how long should it sit before adding the whipped cream to it?

    Reply
    1. Lexi @ Sally's Baking says:
      August 15, 2024

      Hi Sherri, the chocolate mixture should cool just enough while you’re making the whipped cream mixture. If it still seems excessively hot, you can let it cool for another 5 minutes.

      Reply
  29. Karen says:
    August 13, 2024

    Can you use butter instead of vegetable oil?

    Reply
    1. Lexi @ Sally's Baking says:
      August 13, 2024

      Hi Karen, using butter here would yield a dry cake. Best to stick with oil for chocolate cakes!

      Reply
  30. Divya says:
    August 6, 2024

    Why do you not use eggs in the choc mousse sally

    Reply
    1. Lexi @ Sally's Baking says:
      August 6, 2024

      Hi Divya, this is a “simplified” version of mousse compared to other recipes that use eggs or gelatin.

      Reply