Who knew shredded zucchini was the secret ingredient to the best chocolate cake ever? Bursting with rich chocolate flavor and covered in dark chocolate frosting, you’d never know there’s two cups of grated zucchini inside this chocolate cake.
Chocolate Zucchini Cake Recipe
Next time your garden is overflowing with zucchini, head straight for this zucchini chocolate cake! It’s fudgy, indulgent, and everything you want a chocolate cake to be. I promise, no one will guess ZUCCHINI is hiding in there! But it is… 2 wholes cups get folded into the cake batter, ensuring the moistest and most wonderfully textured cake imaginable. Even small children who claim to “hate zucchini” absolutely love this cake.
Ingredients for Chocolate Zucchini Cake
- Zucchini: Use the coarse side of a box grated to coarsely the zucchini. Do NOT drain the zucchini. All of that moisture is what gives this cake its incredible texture.
- Sugar: You’ll need granulated sugar and light brown sugar for the cake, and confectioner’s sugar for the frosting.
- All-Purpose Flour: For best results, you should weigh your flour using a digital kitchen scale. Or lightly spoon it into a measuring cup. But never pack it into the measuring cup. Do not sub any other flour here.
- Unsweetened Cocoa Powder: Measure your cocoa the same way I suggested you measure your flour. Too much cocoa will yield a very dense and dry cake. Dutch-process cocoa powder should not be used here.
- Rising Agents: Baking soda and baking powder get mixed wit the dry ingredients to help the cake spread and rise. Be sure your baking soda and baking powder are fresh.
- Salt: Balances the overall sweetness of the cake and frosting and enhances all of the other flavors in the recipe. It will not make your chocolate cake taste salty.
- Ground Cinnamon: Another “secret ingredient” in this cake, this spice is optional, but definitely adds a wonderful flavor!
- Eggs: Use large eggs and bring them to room temperature before baking. I do not have an egg substitute I can recommend.
- Greek Yogurt: Full-fat sour cream may be used instead. Do not sub milk for this ingredient.
- Oil: Canola oil, vegetive oil, or refined coconut oil (melted) all work fine here. If you don’t mind the flavor of olive oil, I think a mild olive oil would also work well.
- Vanilla: Adds sweet vanilla flavor and enhances all of the other flavors in the recipe.
- Hot Water: Or use an equal amount of hot coffee instead, which enhances the chocolate flavor even more. The key here is for the water, or coffee, to be freshly boiled and hot.
- Butter: The base of the buttercream, I suggest using unsalted butter, but salted will work in a pinch. Simply omit the salt called for in the recipe.
- Chocolate: Use high-quality chocolate, such as Ghiradelli dark chocolate or Guittard semi-sweet chocolate chips. Lesser quality chocolate will not melt smoothly.
- Heavy Cream: Aka heavy whipping cream, do not replace with milk.
Special Equipment for Chocolate Zucchini Cake:
- Cake Pans: You’ll need (3) 9-inch cake pans for this triple layer cake.
- Parchment Paper: To ensure your cakes don’t stick to the bottom of the pans, I suggest lining them with parchment paper rounds.
- Nonstick Baking Spray: You’ll want to spray every nook and cranny with nonstick baking spray to ensure your cakes effortlessly release from the cake pans.
- Electric Mixer: You’ll need a stand mixer or handheld electric mixer for this recipe.
- Box Grater: You’ll need a box grater with a coarse side to properly grate the zucchini.
How to Make Chocolate Zucchini Cake
- Prep Pans: Spray three 9-inch pans with non stick baking spray. Then line them with parchment paper rounds and spray the pans again. Be sure the pans are full coated to avoid you cakes getting stick to the pan. This is also a good time to preheat the oven to 350.
- Make the Cake Batter: In a large bowl combine the dry ingredients, mixing until well combined. In a separate large bowl whisk together the wet ingredients. Fold the wet ingredients into the dry ingredients and mix until just combined. Take care not to over mix, which leads to the cakes rising too much and/or dry cake.
- Bake: The cakes will take about 30 minutes in the oven. You’ll know they’re ready when a toothpick inserted in the center comes out clean, or with just a few moist crumbs attached.
- Cool: Allow the cakes to rest for 10 minutes in the pans. Then carefully remove them from the pans and cool completely on a wire cooling rack. It is crucial the cakes are COMPLETELY cool before you frost them.
- Make the Frosting: Once the cakes are completely cool, you can make your frosting. If it appears too thick, you can thin it out with more cream. If it appears too thin, you can thickened it by adding more confectioners’ sugar.
- Trim the Cakes: Using a serrated knife, trim the raised top of each cake. It’ll be much easier to frost if it’s an even, level surface.
- Assemble: Transfer a cake layer to a large plate or cake stand. Spread a thick layer of frosting evenly across the top of the cake. Top with another cake layer, and repeat this process. Top with the final cake layer and cover the whole cake in frosting.
- Chill: I like to place the cake in the fridge for 20 minutes or so to allow the frosting to firm up. This also helps me cut neat slices that don’t fall apart. If you’re in a rush or don’t have room in your fridge, you can skip this part and serve right away.
Can I make this without Zucchini?
I don’t suggest making this cake without the zucchini. It was developed with these specific ingredients for a reason, and removing one of them will result in less than desirable results. Instead, I suggest trying one of these other fabulous recipes:
More Zucchini Recipes:
- Zucchini Chocolate Cupcakes
- Nutella Stuffed Chocolate Chunk Zucchini Muffins
- Zucchini Chocolate Bundt Cake
Chocolate Zucchini Cake
For the chocolate zucchini cake:
- 2 cups granulated sugar
- 1 cup light brown sugar, packed
- 2 and 1/2 cups all-purpose flour (not packed!)
- 1 and 3/4 cups unsweetened cocoa powder, sifted
- 3 teaspoons baking soda
- 1 and 1/2 teaspoons baking powder
- 1 teaspoon salt
- 1 teaspoon ground cinnamon
- 3 large eggs + 2 large egg yolks, at room temperature
- 2 cups coarsely shredded zucchini, packed and NOT drained (see post for more on this)
- 1 cup full-fat plain Greek yogurt
- 3/4 cup vegetable oil (you may also sub in melted coconut oil)
- 2 teaspoons vanilla extract
- 1 and 1/2 cups hot water
For the fluffy chocolate frosting:
- 1 cup unsalted butter (2 sticks, 8 ounces), VERY soft
- 2 and 1/2 cups confectioners' sugar, sifted
- 6 ounces semi-sweet chocolate, melted and cooled for 10 minutes
- 1 teaspoon vanilla extract
- 1/2 teaspoon salt
- 2 tablespoons heavy cream (more only if needed)
For the chocolate cake:
- Preheat oven to 350°(F). Cut out three 9-inch round segments of parchment paper to line your cake pans with. Spray each pan generously - sides and bottom - with nonstick baking spray, then place the parchment paper cut out in the bottom of the pans and spray again. It's important to make sure every bit of pan and paper are sprayed so your cakes don't get stuck. Set pans aside.
- In the bowl of a stand mixer fitted with the paddle attachment, or in a large bowl using a handheld electric mixer, combine both sugars, flour, cocoa powder, baking soda, baking powder, salt, and cinnamon; mix on low speed until dry ingredients are thoroughly combined. Use your hands to break up any large clumps, if needed.
- In a separate bowl combine the eggs, egg yolks, zucchini, Greek yogurt, oil and vanilla extract; mix until completely combined.
- Pour mixture into the dry ingredients and beat on low until just incorporated. Pour in hot water and continue mixing until completely combined; about 1 minute. The batter will be thin.
- Divide batter evenly among prepared pans. Bake in preheated oven for 30 minutes, or until a wooden toothpick or cake tester inserted in the center of a cake comes out clean or with just a few moist crumbs attached.
- Cool cakes for 10 minutes in the pans before removing from pans and transferring to a cooling rack. Cool cakes completely before frosting. *If you don't have enough room to bake all 3 cakes on the same rack in an even line, bake 2 at a time.
For the fluffy chocolate frosting:
- In a stand mixer fitted with the paddle attachment, or in a large bowl using a handheld electric beater, cream the softened butter on medium-speed until completely smooth; about 3 minutes.
- Turn the mixer off and sift the confectioners' sugar into the mixing bowl. Turn the mixer on the lowest speed and mix until the sugar has been absorbed by the butter; about 2 minutes.
- Increase mixer speed to medium; add in the melted chocolate, vanilla extract, salt, and heavy cream; beat for 2 minutes then increase the speed to medium-high and continue beating for another minute. If your frosting appears too thin, add a little more confectioners' sugar; If your frosting appears too thick, add additional heavy cream, 1 teaspoon at a time.
- Using a serrated knife, carefully trim the raised top of each cake, making each one an even, level surface.
- Transfer 1 layer to a large plate or cake stand. Spread a thick layer of frosting on top, then top with another cake layer, and repeat, thickly spreading it with a layer of frosting.
- Top with the final cake layer and place cake in the fridge to set for 30 minutes. Once set, finishing frosting the top and sides of the cake.
- Slice and serve, or keep refrigerated for about a week.