Chocolate Zucchini Cake

Published on July 16, 2024

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Quick Summary

This moist Chocolate Zucchini Cake with chocolate frosting is easy to make and a family favorite dessert! You will never know there is zucchini in this chocolate cake because it is SO good!

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I LOVE baking with zucchini, especially during the summertime when I have lots of garden zucchini to use up. A few of my favorite zucchini recipes are my Chocolate Zucchini Bread, Zucchini Brownies, Oatmeal Zucchini Cookies, and Lemon Zucchini Bread.

Whenever I am craving a decadent dessert I love making my Chocolate Zucchini Cake. You might be thinking zucchini doesn't belong in chocolate cake, but I am here to tell you it definitely does.

The zucchini makes the chocolate cake SUPER moist and I promise you won't even know it's in there. It is the secret ingredient.

I make the cake in a 9×13-inch pan so decorating is easy and so it will feed a lot of people. The ingredients are basic, you should have all of them on hand.

I top the cake with a luxurious chocolate frosting that takes the cake to a whole new level. The silky, smooth, rich chocolate frosting really is the icing on the cake!

Chocolate lovers will go crazy for this moist, decadent chocolate cake! If you love my classic chocolate cake and easy chocolate cake, I know you will love this one too! It's the perfect summer dessert and a great recipe for using up all of the garden zucchini.

Table of Contents

Cake Ingredients
Chocolate Frosting Ingredients
How to Make Chocolate Zucchini Cake
Recipe Tips
How to Store
More Zucchini Recipes
More Chocolate Cake Recipes
Chocolate Zucchini Cake Recipe

Cake Ingredients

Flour– use all-purpose flour.
Unsweetened cocoa powder– sift before using to avoid any clumps.
Baking soda– to give the cake a nice lift.
Salt– to enhance all of the flavors.
Brown sugar– to sweeten the cake.
Oil– you can use vegetable oil, canola oil, or avocado oil.
Melted butter– cool to room temperature. I like using a mix of oil and butter. The oil keeps the cake moist and the butter adds great flavor.
Buttermilk– at room temperature!
Eggs– use large eggs for baking.
Vanilla extract– use pure vanilla extract, the good stuff!
Zucchini– use a box grater or food processor to shred the zucchini. I never peel it.
Chocolate chips– to stir into the cake batter. Bring on the chocolate!

Chocolate Frosting Ingredients

Butter– at room temperature.
Confectioner's sugar– also called powdered sugar.
Unsweetened cocoa powder– You can sift the confectioner's sugar and cocoa together to guarantee a super smooth frosting.
Milk– to thin out the frosting. Heavy cream will also work.
Vanilla extract– a splash!
Salt– just a pinch!

How to Make Chocolate Zucchini Cake

Preheat oven to 350 degrees F. Grease a 9×13-inch pan with nonstick cooking spray and set aside.
In a medium bowl, combine the flour, sifted cocoa powder, baking soda, and salt. Whisk together and set aside.

In a large bowl, combine the brown sugar, oil, melted butter, buttermilk, eggs, and vanilla extract. Whisk until combined.

Stir in the dry ingredients until barley combined, it is ok if there is still some flour not mixed in.

Gently squeeze out some of the moisture in the zucchini. You want the zucchini to still have some moisture, but not full of liquid. Add the zucchini and chocolate chips and stir until just combined. Don't over mix.

Pour the cake batter in the prepared pan and smooth with a spatula. Bake for 25 to 32 minutes or until a toothpick comes out clean when inserted into the center or the cake.

Let the cake cool completely.

While the cake is cooling, make the chocolate frosting. In the bowl of a stand mixer or with a hand mixer, beat the butter until smooth, about 1 minute. In a large bowl, sift together the confectioner's sugar and the cocoa powder. Add the mixture to the butter and beat, slowly adding in the milk. Add the vanilla extract and salt. Stop and scrape down the sides. Beat until frosting is smooth and fluffy.

Frost the cooled chocolate zucchini cake with chocolate frosting.
Cut the cake into squares and serve.

Recipe Tips

You need 2 cups grated zucchini for this recipe, about 1 very large zucchini or 2 medium.
You don't need to peel the zucchini before shredding it. I use a box grater with a medium grate.
If your zucchini is full of moisture, squeeze it out a little bit, but don't squeeze it dry. Large garden zucchini tends to have more moisture and smaller store bought zucchini. You don't want to get rid of all of the moisture or you will have a dry cake. Just give it a gently squeeze before adding it to the cake.
I use all brown sugar in this zucchini cake recipe because it keeps the cake super moist and adds nice flavor.
The cake is made with oil and butter. The oil keeps the cake super moist and the butter adds great flavor.
Make sure your buttermilk and eggs are at room temperature. Melt the butter and let it cool down a little before adding it to the other liquid ingredients.
Don't over mix the cake. Once you add in the zucchini and chocolate chips, stir just until combined.
I bake this cake in a metal 9×13-inch pan. If you want to make a layered cake, you can pour the batter into two round cake pans.
Make sure the cake is cooled completely before frosting it with the chocolate frosting.

How to Store

The cake will keep on the counter, covered, for up to 3 days. I actually think it is better the second day. If you want to store it for a little longer, you can store it covered in the refrigerator for up to 5 days. Bring to room temperature before serving. I also think it is good cold:)
You can make the cake in advance and freeze the cake. Let it cool completely. Carefully wrap the cake in plastic wrap and foil. Place in the freezer and freeze for up to 3 months. Thaw and frost with chocolate buttercream.

More Zucchini Recipes

Chocolate Chip Zucchini Bread
Chocolate Zucchini Bread
Zucchini Brownies
Zucchini Muffins
Lemon Zucchini Bread
Brown Butter Zucchini Oatmeal Chocolate Chip Cookies

You can find more zucchini recipes here!

Cake