Super moist and indulgent chocolate zucchini cake is studded with chocolate chips and topped with chocolate fudge frosting. Made with 3 cups of shredded zucchini (you can’t taste it!), this is the most decadent way to eat your greens.
I originally published this recipe in 2017 and have since added new photos, a video tutorial, and additional success tips.
Today, we have a triple dose of chocolate in the form of luxuriously rich chocolate zucchini cake. No, you can’t taste the zucchini. No, you can’t see the zucchini. Yes, it’s unbelievably delicious and I’m showing you exactly how to make it! Zucchini recipes have never been more decadent than this one. 🙂
Can you just look at how rich and moist this cake is? It tastes even better than it looks, I swear. The real secret behind it is the hidden vegetable inside. If you’re one who believes these veggies should only be in zucchini casserole, zucchini fritters, or zucchini biscuits and have nothing to do with dessert, keep an open mind. Carrot cake, anyone?!
Why You’ll Love This Chocolate Zucchini Cake
- Just as loved as my chocolate cake
- Super moist and rich with mega chocolate flavor
- Easy to make
- A delicious way to use up a bumper crop of summer zucchini
- 3 cups of vegetables hiding inside—and you don’t even taste it
- Covered in fudge-like chocolate buttercream
One reader, Stacie, commented: “Delicious chocolate cake! No evidence of three cups of zucchini in there! So good!!! ★★★★★“
One reader, Emily, commented: “This was amazing! Probably the best chocolate cake we’ve ever had—so moist! And no one even guessed there was zucchini in it. ★★★★★“
One reader, Kara, commented: “This wasn’t just the best zucchini recipe I’ve ever tried, it was the best cake recipe as well! The zucchini here makes this moist and fudgy, almost like a brownie, but still fluffy like cake. I used cream cheese frosting and it was divine. I will be making this for birthdays in the future! ★★★★★“
Overview: Chocolate Zucchini Cake Ingredients
This decadent cake is made with fresh zucchini and pantry basics. Did you know that cocoa powder can dry out baked goods much more than flour? To compensate for this, we ensure there’s plenty of added moisture in the cake batter.
Let’s review a few key ingredients:
- Unsweetened Natural Cocoa Powder: Cocoa powder takes the place of some flour. Just as in my regular chocolate cake recipe, make sure you’re using natural unsweetened cocoa powder instead of Dutch-process cocoa powder.
- Espresso Powder: Espresso powder accentuates the chocolate flavor. While optional, I highly recommend using it. The chocolate zucchini cake won’t taste like coffee. Rather, the espresso powder helps bring out the intense chocolate flavor. We use it in chocolate zucchini bread and in this chocolate cake roll, too. You can find espresso powder in the coffee aisle at the grocery store or online.
- Oil: Oil adds moisture. You can try replacing *some* of the oil with unsweetened applesauce. I’ve done this with chocolate cakes and muffins and the result is wonderful, but I don’t recommend replacing all of it. Despite the zucchini inside, this isn’t health food, it’s dessert. Don’t try to make it into something it’s not!
- Eggs: 4 eggs bind everything together and add moisture. Remember that room-temperature ingredients are important.
- Sour Cream: Just like in chocolate peanut butter cake, you can use sour cream or plain yogurt. Either add moisture.
- Zucchini: Use a whopping 3 cups of shredded zucchini in this recipe. Testing how much we can get away with… without actually tasting it! Zucchini is pure magic in cakes—nothing but flavorless moisture. Same goes with my zucchini bread, apple zucchini bread, and zucchini muffins, too!
Optional Chocolate Chips: For mega chocolate flavor, add chocolate chips to the batter. They’re key to those melty pockets of chocolate in each slice. I use semi-sweet chocolate chips (just like in my peanut butter chocolate chip zucchini bread), but mini chocolate chips or even dark chocolate chips pair wonderfully, too.
Let Me Show You How to Make It:
This chocolate zucchini cake comes together quickly and easily, just like my regular zucchini cake. Simply whisk the dry ingredients in one bowl and beat the wet ingredients together in another bowl. Combine the wet and dry ingredients, then add the chocolate chips. The cake batter will be slightly thick thanks to all of the zucchini! Divide the batter between two 9-inch cake pans; or you can make a quarter sheet cake using a 9×13-inch cake pan. See the recipe Notes section for details.
- Need cupcakes instead? This recipe yields about 24–30 cupcakes. See recipe Notes.
Chocolate Frosting
We’re topping and filling this chocolate zucchini cake with smooth, silky, and creamy chocolate buttercream. You’ll use my favorite chocolate buttercream recipe, but increase the quantity as directed in the recipe card below.
How to Assemble a Layer Cake
If you’re new to assembling and layering cakes, or if you just need a refresher, see my How to Assemble a Layer Cake video tutorial. The quick video guide will walk you through how to stack and decorate it.
If you would rather top this cake with vanilla frosting, use the vanilla frosting included in my white cake recipe. Regardless of which you choose, you’ll have enough frosting to frost the entire layer cake AND a little leftover for some fun piping on top. Decorate however you’d like! I used Wilton 1M for the pictured piping:
Deep, dark, luxuriously rich, crazy moist, and weirdly loaded with vegetables that you absolutely can’t taste. After one bite you’ll be convinced this is the best way to eat your veggies! You’ll love my zucchini oatmeal chocolate chip cookies, too.
More Chocolate Recipes
- Chocolate Lava Cakes
- Flourless Chocolate Cake
- Chocolate Cake
- Chocolate Cupcakes
- Homemade Brownies
- Inside Out Chocolate Chip Cookies & Double Chocolate Chip Cookies
Chocolate Zucchini Cake
- Prep Time: 15 minutes
- Cook Time: 30 minutes
- Total Time: 3 hours, 30 minutes
- Yield: serves 10-12
- Category: Dessert
- Method: Baking
- Cuisine: American
Description
This super rich and moist chocolate zucchini cake is topped with the best chocolate frosting—you won’t even taste the vegetables!
Ingredients
Cake
- 2 cups (250g) all-purpose flour (spooned & leveled)
- 3/4 cup (62g) unsweetened natural cocoa powder
- 2 teaspoons baking soda
- 1/2 teaspoon baking powder
- 1 teaspoon espresso powder (optional)
- 1/2 teaspoon salt
- 1 cup (240ml) canola or vegetable oil
- 1 cup (200g) granulated sugar
- 3/4 cup (150g) packed light or dark brown sugar
- 4 large eggs, at room temperature
- 1/3 cup (80g) sour cream or plain yogurt, at room temperature
- 2 teaspoons pure vanilla extract
- 3 cups (about 360g) shredded zucchini (lightly blotted; see recipe Note) (2 medium zucchini, about .75–1 lb.)
- 1 cup (180g) semi-sweet chocolate chips (regular or mini)
Chocolate Buttercream
- 1 and 1/4 cups (282g) unsalted butter, softened to room temperature
- 3 and 1/2 cups (420g) confectioners’ sugar
- 3/4 cup (62g) unsweetened cocoa powder (natural or Dutch-process)
- 3–5 Tablespoons (45–75ml) heavy cream (or half-and-half or whole milk), at room temperature
- 1/4 teaspoon salt
- 1 teaspoon pure vanilla extract
- optional for decoration: chocolate chips and/or chocolate sprinkles
Instructions
- Preheat oven to 350°F (177°C). Grease two 9-inch round 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.)
- Make the cake: Whisk the flour, cocoa powder, baking soda, baking powder, espresso powder (if using), and salt together in a large bowl. In another large bowl using a handheld or stand mixer fitted with a paddle attachment, beat the oil, granulated sugar, brown sugar, eggs, sour cream, and vanilla together until combined. Add the zucchini and mix to incorporate. Add the dry ingredients to the batter and beat on medium speed until completely combined. Fold in the chocolate chips. Batter will be slightly thick.
- Pour batter evenly into cake pans. Bake for around 28–32 minutes or until the cakes are baked through. To test for doneness, lightly poke the top of the cake with your finger—if it bounces back instead of leaving , the cake is done. Or you can insert a toothpick into the center of the cake—if it comes out clean, it’s done.
- Set the cakes on a cooling rack and let cool in the pans for 1 hour. After 1 hour, remove the cakes from the pans, discard the parchment rounds, and let the cakes finish cooling directly on the rack. The cakes must be completely cool before frosting and assembling.
- Make the buttercream: With a handheld or stand mixer fitted with a paddle attachment, beat the butter on medium speed until creamy, about 2 minutes. Add confectioners’ sugar, cocoa powder, 3 Tablespoons of cream, salt, and vanilla. Beat on low speed for 30 seconds, then gradually increase to high speed and beat until it’s smooth and creamy. Do not over-whip. Add 1/4 cup more confectioners’ sugar or cocoa powder if frosting is too thin or 1–2 more Tablespoons of cream if frosting is too thick. (I usually add 1 more.) Taste. Add another pinch of salt if desired.
- Assemble and frost: First, using a large serrated knife, slice a thin layer off the tops of the cakes to create a flat surface. Discard (or crumble over ice cream!). Place 1 cake layer on your cake stand, cake turntable, or serving plate. Evenly cover the top with a heaping cup of frosting. Top with 2nd cake layer and spread the remaining frosting all over the top and sides. Pipe any leftover frosting on top. (I used Wilton 1M tip.) Decorate with chocolate sprinkles or chocolate chips if desired. Slice and serve.
- Cover leftover cake and store at room temperature for up to 2 days or in the refrigerator for up to 5 days.
Notes
- Make Ahead Instructions: Prepare cakes and frosting 1 day in advance. Keep cakes at room temperature, covered tightly. Refrigerate prepared frosting in an airtight container, then bring to room temperature when ready to use. Frosted or unfrosted cakes may be frozen up to 2 months, thaw overnight in the refrigerator and bring to room temperature, if desired, before serving.
- Special Tools (affiliate links): Box Grater | Glass Mixing Bowls | Electric Mixer (Handheld or Stand) | 9-inch Round Cake Pan | Cake Turntable | Wilton 1M Piping Tip | Piping Bag (Reusable or Disposable) | Cake Carrier (for storage)
- Blot the Zucchini: Give the shredded zucchini a very light blotting with a towel. Don’t squeeze too much moisture out, just a little blot before adding to the wet ingredients. I own and love this box grater—works quickly!
- 9×13-inch Cake: Interested in making a sheet cake instead? This batter will fit into a 9×13-inch pan. The bake time is long—at least 45 minutes to ensure the thick cake is baked through. Same oven temperature.
- Non-Chocolate Zucchini Cake: Looking for zucchini cake without chocolate? Here is my regular zucchini cake topped with brown butter cream cheese frosting.
- Cupcakes: This recipe yields 24–30 cupcakes. Bake for 18–22 minutes or until a toothpick inserted in the center comes out *mostly* clean with no wet batter. Same oven temperature.
Instead of cake, try these as cupcakes! Directions in the recipe Notes above.
Reader Comments and Reviews
This recipe looks amazing and I can’t wait to try it. I’m wondering if a cream cheese frosting would work with this recipe. Thoughts?
Hi Lisa, Yes a tangy cream cheese frosting would be delicious with this chocolatey cake!
Can I use an egg replacement? All of my kids are allergic to egg, soy, peanut & apple. TIA!
Hi Kara, The 4 eggs bind everything together and add moisture. We haven’t tested this recipe with any egg substitutes but let us know if you try anything!
This is one of the most delicious cakes that I have have ever eaten!
I am blown away, and the fact that there is zucchini in it ( which you cannot tell is there)is just a bonus… you get to feel like there’s something healthy in there!
I’m going to throw away all my other Chocolate Cake recipes and this is THE only one I will make from now on!
Thank you Sally!!!
This was a huge hit with my family and guests! Thanks so much for the recipe.
This recipe looks wonderful. I am wondering if anyone tried it in a loaf pan? I’m wondering what the cooking time would be?
Hi Erin! This would work well divided between two loaf pans. Fill them half way, and use any leftover batter for a few cupcakes. We’re unsure of the exact bake time.
Hi sally! i looove this recepy, but always have doubts with the coffee. Do you use instant coffee or regular espresso coffee?? The one you use to brew coffee in an espresso machine? (Sorry if it sounds like a silly question! Where I live instant espresso coffee doesn’t exists)
Hi Patricia! We use espresso powder (sold as such near the coffee in grocery stores), not actual liquid coffee or espresso. You can omit it if needed!
I love this recipe! I also love dark chocolate and was wondering if I could substitute that in this recipe? Thanks!
Hi Heidi! You can definitely use dark chocolate chips this recipe. Enjoy!
Would this recipe work well as the base for a black forest cake?
Hi Jess, we can’t see why not. Let us know what you try!
I tested this recipe for an upcoming baby shower, made them into cupcakes and my family couldn’t gobble them up fast enough. Managed to save a couple to see how fresh they would be days later and they were still moist and fresh. Even made a batch of them with GF flour (3 kids are coeliacs) and I couldn’t taste the difference. Fantastic recipe. I’ve been informed I now I have to make more for my grandson’s birthday…well off to the kitchen I go…
What GF flour did you use? I came on here to read comments and see if anyone had tried GF yet!
Patti, I use different ones – depends on what’s available when I need it. At the moment I’m using Woolworths ‘free from gluten’ plain flour and have had decent results. I’m very picky with the flours as I want my kid’s food to taste as good as normal baked goods. I’m in Australia. Not sure what’s available worldwide – it can be a bit a ‘trial and error’ until you find one that works well.
Delicious, dark and moist chocolate cake that the secret ingredient remains a secret! I made the cake exactly as the recipe called for and the only thing that I had to modify was the baking time. I needed to bake my two 9 inch round cakes for 47 minutes before they tested done. This is a great recipe and we will use it as a go to during zucchini season!
I love the cake, I used 3 – 8 inch pans and baked until tooth pick out clean. Next time I will but parchment on pan bottoms and blot zucchini more. I will make again, and spiked your Chocolate buttercream frosting with some dark rum. Cake was awesome, will make again
Can you do this with fewer zucchini without sacrificing quality of the batter? Or replace with a different vegetable?
Shredded apple or carrot works too!
I am planning on making this cake within the next week and am wondering about how many zucchinis to buy. Thanks so much!!
Hi Kate! You should need about 3 medium zucchinis. Hope you love this cake!
Can you bake cake in 3 8-inch layers instead of 2? I like the look of a taller cake, it’s for Father’s Day.
Hi Carmen! We don’t see why not. Bake time will be shorter with thinner layers, so keep an eye on them in the oven. We hope this cake is a hit for Father’s Day!
This cake is excellent and so easy to make. I add fresh raspberries in the centre and on top.
Can you replace the yogurt/sourcream with apple sauce?
Hi Brielle, We haven’t tested that substitution. It may result in a less soft cake, but let us know if you try it!
Hi Sally, I made this cake and everyone loved it. Was my first time and came out very good, very moist and most of all wasn’t that sweet, so my husband is diabetic and he enjoy it.
I’ve made this cake several times and it’s always a huge hit! It’s ridiculously moist and super delicious.
My 14 year old daughter made this for my birthday cake using both Hershey’s Special Dark and unsweetened cocoa powder. It was AMAZING! Thanks for the recipe.
Would this cake still turn out if I only had 1 cup of shredded zucchini?
Hi Tara! We suggest sticking with the full amount of zucchini, otherwise it will be too dry. You may love this chocolate cake without zucchini as well!
Thanks for sharing your recipe it’s the best zucchini cake ever! Where ça I find the chocolate frosting recipe I see the video but not the recipe?
Hi Colette, it’s linked at the bottom of the recipe ingredients. Use the frosting from this Triple Chocolate Cake recipe. Hope you love this cake!
Delicious and so moist!! Yum!
I love this cake but I can’t quite give it 5 stars as I made a couple of modifications. I used milk chocolate morsels (because that’s what my husband bought, smh) so I decided to cut down the white sugar by 1/2 cup. I also substituted avocado mayo for sour cream because we didn’t have any. Instead of baking 2 cakes, I made a 9×9 and 12 cupcakes. I think maybe the mayo or the difference in baking proportions may have affected the baking time. I ended up baking the cake for close to 40 min (cupcakes were done by 20). Frosting the cake was difficult as it was so moist and soft even after refrigerating overnight. I didn’t mind too much though as we love frosting.
Just one question, how do you keep the chocolate morsels from sinking to the bottom? When I was scooping out the batter into the cupcake pan, I found much of the morsels left at the bottom of the bowl. And when I popped my cake out of the pan, the morsels at the bottom were actually left sticking to the pan. The cake was left looking like swiss cheese on one side. There were still morsels left in the cake but not a lot.
Thank You!! It turned out Awesome
My husband and I agree that this is the best chocolate cake we’ve ever eaten, zucchini or no zucchini. I’ve made it twice and savored every bite! Fantastic!
Could it be baked in a glass 9×13? Would the time and temperature need to change?
Yes it can, Rachel! See the recipe notes for directions.
About to make this today for a disbelieving partner. Most happy to see UK grams listed in the instructions already. Thank you.
This is a fabulous recipe! Not too sweet, lusciously chocolatey, and moist! I was wondering if you offer nutrition information for your recipes?
I just won best dessert at a Zucchini Festival with this recipe. It was a big hit! I added some chopped pecans to the batter and a teaspoon of instant coffee to the frosting. So good!
I don’t know what I did, this did not turn out at all. Doesn’t taste very chocolatey, but the texture is good.