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
I was given fresh zucchini by my co-worker and wanted to bake a cake. As a new follower to your site, I looked up this recipe. This cake is amazing. Quick and easy to make with a moist deep chocolate taste. I baked mine in a 9×13 pan and used a Cream Cheese frosting. Thank you so much!
This made delicious cupcakes and my zucchini hating husband had NO idea it was in there! (I like my own buttercream frosting better than yours though- sorry!)
my kids and I just LOVE this cake! I made it into cupcakes and It was quiet a success. The great thing that it was loaded with zucchini which my picky kids usually wouldn’t touch, yet they ate all of it.thank you Sally!
Made this cake for the first time— winner! They couldn’t wait for the icing, but added ice cream! Next time I will have the icing made first so I can add it before they eat it all! It’s my go to recipe now and I will be making it again and again! Thank you Sally!
Mine is in the oven right now. Taking on vacation with us. Hope it turns out. Never baked with zucchini before. And didnt know there was a tip section at the very bottom of the page. I didnt get any liquid out of the zucchini. Would be great if that was mentioned right in the recipe. I’m sure first time zucchini users would appreciate this. We’ll see how it turns out.
Super good!
Did muffin tins and it made 29 muffins, cooking for ONLY 19 MINUTES, so be sure to keep an eye on these smaller quantities, and check with a toothpick as instructed.
I’ve made this cake three times since July. Each time we shared it with either family or friends, and each time we were asked for the recipe. Excellent chocolate cake.
I have now made this cake a number of times and we as a family adore it!! Always the same great result, I would recommend ( and have done ) it over and over.
Thank you Sally for another great recipe!!
Unfortunately I don’t like chocolate, but I made cupcakes for a family get together and everyone LOVED them! I will definitely make them again… they were super moist and no one noticed the zucchini!
Hi..this is a wonderful recipe..l used organic coconut sugar instead of white granulated..and used 3/4 cup demera brown sugar.l used grapeseed oil..it all worked together super good..just a nice moist texture..will be making this often..thank you…
Thanks again Sally! This recipe has saved me going bonkers with an overflow of zucchine. A mahoosive hit with my italian friends, family and neighbours who had never considered zucchini as a cake ingredient! I used a paleo ganache instead of the frosting as also very simple and easier to just pour and chill – coconut milk, chocolate and a pinch of salt!
Last question is how diabetic friendly is it? I have made it gluten free a few times but not sure how to make it diabetic friendly
Hi Sheena, We are so happy that this recipe was such a hit with your friends and family! We haven’t tested it with any sugar substitutes but let us know if you try.
Made this just as written and it was wonderful. Will definitely make it again.
I’ve made this twice in the last week, once for my coworkers & once for my kids & it was a hit! However, for my kids I substituted half the flour for ground rolled oats, decreased the sugar by 1 cup and increased the chocolate chips by 1/4 cup and omitted the frosting. They couldn’t get enough! Thanks Sally! I’ve been using your recipes for years!!
Do you think I could make this in three pans? I just have the regular cake pans but I’m worried they aren’t deep dish like you mention. Would it change the bake time? Thanks!
Hi Raina, Making it into a three layer cake would be just fine. Each layer will be thinner so the bake time will likely be shorter. Hope you love it!
I have made this twice already and getting ready to make it again. It is so moist an fine. I replaced 1/3 cup of oil with applesauce and used your chocolate frosting recipe and I got by with reducing the butter to 3/4 cup. I made cupcakes and froze them! Lol we even eat them frozen! Thank you for this delicious recipe!
Holy crap. This is amazing. There is no good reason to do anything else with zucchini.
No one could believe they were having one of their 5 a day!
Absolutely gorgeous about to make them again!
This cake is amazing! My 9” cake pans are shallow so I ended up with 3 perfect layers. The icing recipe yielded plenty of icing to allow for the extra layer. I also made it using your peanut butter icing between the layers, replaced the chocolate chips with peanut butter chips. Finished it with the chocolate icing and decorated with Reece’s pieces and mini Reece’s cups. OMG!
I made this! I used almond yogurt, as it was all I had, this cake turned out amazing! Super moist, super yummy! Total hit with the family! Definitely going in my rotation! I LOVE the veggies in there! Thank you so much for sharing!
Love this recipe. Used a different frosting because I was hungry for a peanut butter fudge frosting. Gave half of the cake to a neighbor and the family loved it. (The dad gave us 3 zucchini and I had to get a good recipe to use some of the zucchini.) Thank you so much for the recipe.
I just made this cake to help with my over abundance of zucchini. Not only does it help with that but it’s one of the best chocolate cakes I’ve ever made or tasted. It’s so moist and flavorful. I made the chocolate frosting recipe and that is incredible too. I’m new to Sally’s site but will definitely be making other tasty delights and will keep you posted.
Made this with 3 substitutions: unsweetened applesauce for half the oil, instant coffee for espresso, and Splenda for half the sugar. Delicious! For those that didn’t make the frosting…you really should. The best buttercream I’ve ever made and the layered cake looks so impressive but isn’t that hard!
Wow! This cake recipe is AMAZING! You can’t even tell there’s zucchini in it! I will be using this recipe as my go-to recipe for chocolate cake from now on. Thank you!
This was the best chocolate cake I have ever made or tasted!!!!
Thank you for this great recipe……..By far, this is the most delicious cake EVER………A very moist and flavorful cake with no hint of the “surprise” ingredient …zucchini. A keeper recipe for sure.
What can you substitute for expresso powder? I have instant coffee granules. Can I use those instead?
Sure can! I’d use 1 and 1/2 teaspoons (or up to 2 tsp) instant coffee in this cake.
Cannot WAIT to make this!!! It looks totally yummy! We have a lot of zucchini from our garden this year so I’m on the hunt for different ways to use it. Do you know if this would bake nicely in a bundt pan?? I haven’t read any comments on that yet.
I made this GLUTEN FREE and is was DELICIOUS!!! No one even knew. I used Krusteaz all purpose GF flour. This cake is insanely good. Definitely a keeper!!
Honestly hands down the best Chocolate cake ive ever made. Zucchini what!!! You will never no its in there. Delicious.
can i use greek yogurt instead of plain?
Yes, plain Greek yogurt works. Enjoy!