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Chocolate Zucchini Cake

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Chocolate zucchini cake is rich, ultra-moist and the perfect cake for the chocolate lover in your life.

Close up of a slice of chocolate zucchini cake with a bite taken from the corner. A fork is visible perched on the side of the plate.

Although it’s only mid-August, my social feeds are full of pumpkin and apple recipes already and I’m over here like, can we just enjoy the last couple of weeks of summer?

While I can’t get behind the pumpkin recipes just yet (gimme two weeks), I can totally get behind the zucchini recipes, especially when my neighbors passed along two of them straight from their garden last week. 

This chocolate zucchini cake is rich and delicious and I promise you, even my zucchini-hating husband had no idea it was packed with over 2 cups of freshly grated zucchini!

Ingredients for chocolate zucchini cake arranged on a gray countertop.

ULTRA-RICH CHOCOLATE ZUCCHINI CAKE

I’m the only one in my household who likes zucchini in its natural state. 

This means that when I end up with extra zucchini, I’m better off hiding it in baked goods like zucchini banana bread, chocolate zucchini muffins, and this chocolate zucchini cake.

Nothing like sneaking a little zucchini into a chocolate cake, right? I guess cake kind of defeats the purpose of eating a vegetable, but we can overlook that fact.

If you have a chocolate lover in your life, this is a must-make even if that chocolate lover happens to be a zucchini hater. I promise, they won’t be able to detect the zucchini – especially if you shred it super fine.

This chocolate zucchini cake is rich, ultra-moist, and fudgy. I’ve served the cake up with just a simple dusting of powdered sugar, but it really reaches its full potential with a layer of silky ganache.

I mean, more is always more, right?

Chocolate cake batter base for chocolate zucchini cake in a white mixing bowl.

HOW TO MAKE THIS CHOCOLATE ZUCCHINI CAKE

If you love the best chocolate cake and black magic cake, you have to give this recipe a try. Let’s talk through how to make it!

Ingredients you’ll need

There are a few key ingredients in this recipe that help to make it super moist and fudgy:

Vegetable oil: This recipe uses a bit of butter for flavor combined with vegetable oil for texture. Because cocoa powder can often dry out cakes, using vegetable oil helps combat that and keep the cake moist.

Sour cream: Remember how in my post on how to make buttermilk we talked about using sour cream as a substitute for buttermilk? Sour cream also keeps the cake moist and adds a lovely tangy flavor.

Shredded zucchini: Zucchini has a good amount of water in it, so it always lends a nice rich texture to any baked good you put it in!

Chocolate zucchini cake batter being stirred in a white mixing bowl.

Chocolate chips: To make this cake extra chocolatey and fudgy, we’ll add chocolate chips in addition to the cocoa powder. You’ll love those little pockets of chocolate throughout the cake!

Other ingredients you’ll need for this cake include:

  • Granulated sugar
  • Vanilla
  • Baking soda
  • Baking powder
  • Salt
  • Eggs
  • All-purpose flour
  • Dutch-process cocoa

Make sure you know how to measure flour properly so you always have success with this recipe!

Chocolate zucchini cake batter spread into a pan, ready to bake.

What is dutch-process cocoa powder? 

There are two main kinds of cocoa powder: natural cocoa and dutch-process cocoa.

Dutch-process cocoa has been treated to reduce the acidity of the cocoa powder, which gives it a darker color and less bitter flavor than natural cocoa. 

Using dutch-process cocoa in this recipe will help give it that deep, rich color and help avoid any bitter flavor. It will be pure, sweet, chocolate goodness! 

If you don’t have dutch-process cocoa on hand, simply use your favorite unsweetened cocoa powder and add in an extra ½ teaspoon of baking soda to the dry ingredients. Easy-peasy and no need to make a special run to the store.

Baked chocolate zucchini cake set next to a bowl of chocolate ganache frosting.

Making this recipe

In a bowl, cream together the butter, oil, sugar, vanilla, baking soda, baking powder, and salt.

I know that this order of operations is a bit different than what we’re used to with most cake recipes, but trust me – it works.

Add in the eggs, then alternate stirring in the sour cream with the flour. Finally, add the cocoa powder and mix until well combined and the batter is smooth.

Frosted chocolate zucchini cake on a piece of parchment paper.

Fold in the shredded zucchini and the chocolate chips. The batter will be quite thick!

Spread the batter in a greased 13×9-inch pan and bake for 30-35 minutes. The top of the cake should spring back lightly when touched.

Let the cake cool in the pan completely before topping with the ganache.

When you’re ready to add the ganache frosting, heat the cream in a saucepan over medium heat until simmering. 

Two plates of chocolate zucchini cake next to cups of espresso.

Remove the cream from the heat and pour it over the chocolate chips, then whisk to combine. Be patient – it might take a few minutes for the ganache to start to come together.

The ganache will seem quite runny at first, but it will thicken as it cools. I like to let it cool until it’s just slightly warm and still pourable, then I pour it over the cake and smooth it over the top.

Let the frosting set for about 30 minutes before cutting and serving.

Sliced chocolate zucchini cake on a piece of parchment paper.

STORAGE TIPS

Because the cake is very moist and topped with a ganache, make sure to store any leftovers in the refrigerator. The cake will keep, covered in the fridge, for up to 3 days.

If you’d like to freeze the whole cake, I recommend doing so before adding the ganache. Then you can top it with the ganache after thawing and before serving.

If you want to freeze leftover slices of cake, you can wrap them tightly and freeze them for up to 1 month. Just know that the ganache frosting won’t look very pretty after it thaws, but it will still taste delicious.

Give this chocolate zucchini cake a try – it’s sure to impress any chocolate lover!

Slice of chocolate zucchini cake set on a white plate. A bite has been taken from the corner of the cake.
Slice of chocolate zucchini cake with a bite taken out of the corner.

Chocolate Zucchini Cake

Yield: 15 servings
Prep Time: 15 minutes
Cook Time: 35 minutes
Cool Time: 30 minutes
Total Time: 1 hour 20 minutes

Chocolate zucchini cake is rich, ultra-moist and the perfect cake for the chocolate lover in your life.

Ingredients

For the Cake

  • 1/2 cup unsalted butter, softened
  • 1/2 cup vegetable oil
  • 1 3/4 cups granulated sugar
  • 1 teaspoon vanilla
  • 1 teaspoon baking soda
  • 1/2 teaspoon baking powder
  • 1/2 teaspoon salt
  • 2 large eggs
  • 1/2 cup sour cream
  • 2 1/2 cups all-purpose flour
  • 3/4 cup Dutch-process cocoa*
  • 2 1/2 cups shredded zucchini
  • 2/3 cup chocolate chips

For the Chocolate Ganache

  • 3/4 cup heavy cream
  • 10 ounces semi-sweet chocolate chips

Instructions

For the Cake

  1. Preheat the oven to 325°F. Lightly grease a 9 x 13-inch pan.
  2. In a large mixing bowl, cream together the butter, oil, sugar, vanilla, baking soda, baking powder, and salt.
  3. Add in the eggs. Stir in the sour cream alternately with the flour. Then add the cocoa powder and mix until incorporated and the batter is smooth. Fold in the zucchini and 2/3 cup chocolate chips. Batter will be thick.
  4. Spread the batter to the edges of the prepared pan and bake the cake for 30 to 35 minutes, till the top springs back lightly when touched. Place pan on a wire rack to cool completely.

For the Chocolate Ganache

  1. To prepare the frosting, heat the heavy cream in a saucepan over medium heat until simmering.
  2. Remove the cream from the heat and pour it over the chocolate chips. Whisk to combine. It may take a few minutes of stirring for the ganache to come together, but I promise it will. The ganache will thicken as it cools.
  3. Allow the ganache too cool until just slightly warm and still pourable. Pour the ganache over the cake and smooth with offset spatula. Allow frosting to set for about 30 minutes before serving.

Notes

*If you are using regular unsweetened cocoa powder, add an additional 1/2 teaspoon of baking soda.

Store leftover chocolate zucchini cake in the fridge for up to 3 days.

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Nutrition Information
Yield 15 Serving Size 1 slice
Amount Per Serving Calories 472Total Fat 27gSaturated Fat 12gTrans Fat 0gUnsaturated Fat 13gCholesterol 59mgSodium 191mgCarbohydrates 57gFiber 3gSugar 36gProtein 6g

Did you make this recipe?

Tag me on social! I want to see what you made! @jamiemba

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Christopher

Friday 30th of September 2022

Can you add nuts to this? Like roasted pecans?

Deborah

Monday 19th of September 2022

Hi there! This recipe is just beyond delicious! It is the best chocolate cake I have ever eaten! I sent this recipe to my Mom first because I knew she had zucchini in her garden to cook with. I hadn't tried it myself as of yet. She made it shortly after I sent the recipe to her and shared some with me. So kind. It was heavenly! I now have one in my oven baking and will bless her and Dad with some tonight. Thank you so much for sharing this recipe with us. I will post it to my instagram this evening too!

xo Deborah

Jamie

Thursday 22nd of September 2022

I’m so glad you love the cake, Deborah! Thanks for stopping by and leaving your feedback! Happy baking – Jamie

Patricia

Thursday 18th of August 2022

Looks delicious! Can’t wait to make it. Is there a brand of dutch-process cocoa powder you recommend? I have several recipes that call for it but not sure which brand is best to order. Thanks!

Jamie

Tuesday 23rd of August 2022

Hi Patricia – I don't have a particular brand I use, but you can never go wrong with King Arthur products! Hope this helps. Happy baking! Jamie

Alicia

Wednesday 17th of August 2022

Looks fantastic! Would a little instant espresso powder work in this recipe?

Jamie

Thursday 18th of August 2022

Hi Alicia – I haven't tried this recipe with instant espresso powder, so I'm not 100% sure of the result. If you give it a try, I'd love to know how it turns out! Happy baking! Jamie

Trudy

Sunday 7th of June 2020

Is there a vegan option?  Please email me the recipe.  Thanks in advanced.

Jamie

Wednesday 10th of June 2020

Hello! I haven't attempted this recipe as a vegan cake, so I am not sure of the best method. If you happen to give it a try, I'd love to know how it turned out. Thanks so much for stopping by. -Jamie

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