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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.
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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.
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Chocolate Zucchini Cake

By: Jamie Lothridge
4.48 from 17 ratings
Prep: 15 minutes
Cook: 35 minutes
Cool Time: 30 minutes
Total: 1 hour 20 minutes
Servings: 15 servings
Chocolate zucchini cake is rich, ultra-moist and the perfect cake for the chocolate lover in your life.

Ingredients

For the Cake

For the Chocolate Ganache

Instructions 

For the Cake

  • Preheat the oven to 325°F. Lightly grease a 9 x 13-inch pan.
  • In a large mixing bowl, cream together the butter, oil, sugar, vanilla, baking soda, baking powder, and salt.
  • 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.
  • 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

  • To prepare the frosting, heat the heavy cream in a saucepan over medium heat until simmering.
  • 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.
  • 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.

Nutrition

Serving: 1slice, Calories: 472kcal, Carbohydrates: 57g, Protein: 6g, Fat: 27g, Saturated Fat: 12g, Polyunsaturated Fat: 13g, Cholesterol: 59mg, Sodium: 191mg, Fiber: 3g, Sugar: 36g

Nutrition information is automatically calculated, so should only be used as an approximation.

4.48 from 17 votes (17 ratings without comment)

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67 Comments

  1. Nicole says:

    Jamie, Is this the same cake that you baked in a bundt cake pan? I swear at one time on my pinterest board I had a recipe from you for a chocolate zucchini bundt cake. It was an all time favorite and now I can’t find it.

    Thanks

    1. Jamie says:

      Thanks so much for stopping by, Nicole! I actually don’t believe I’ve ever made a chocolate zucchini bundt cake. I appreciate you taking the time to comment. Happy Baking!
      -Jamie

  2. Julie says:

    I made this today because I have a lot of zucchini coming out of the garden. I omitted the oil, reduced the sugar to 1 cup, swapped Greek yogurt for sour cream. I baked it in a bundt pan for 40 minutes at 325 F. I think it should have stayed in the oven for 5-10 minutes longer & been perfect. I really like this recipe and the ganache is perfect!

    1. Jamie says:

      So happy to hear you enjoyed the cake, Julie! Thanks so much for stopping by and leaving your feedback!
      -Jamie

  3. Donna says:

    This cake is awesome! I got the recipe from your site in 2009, and have been making it since. We plant zucchini and always end up with more than we can eat, so I decided to make it that year, and am so glad I did! It is the most moist cake I have ever eaten, and the ganache is the perfect topping!

    Family and friends rave about how good it is!

    1. Jamie says:

      So happy to hear you’ve enjoyed the recipe since way back in 2009. It’s one of our absolute favorites! I love that you use homegrown zucchini – I bet that makes it even more special!
      -Jamie

  4. jeannie says:

    I put this cake in an 8 inch round wilton cake pan, it’s been in the oven for well over 50 minutes. Am I doing something wrong!?

    1. Jamie says:

      Jeannie-
      This recipe calls for a 9×13 inch pan, not an 8-inch round pan. The area of the pan you used in much smaller than a 9×13. I hope this helps you problem solve the overflowing cake.
      -Jamie

  5. Gina says:

    My son loved this cake (and he hates zucchini). hee hee hee.

    1. Jamie says:

      Kids would never suspect the zucchini! Thanks for stopping by.

      -Jamie

  6. Gina says:

    I just made this same cake last week for book club, but sent it over the top with German Chocolate Frosting. We stopped talking about the book once the cake was served!

    My recipe came from an old church cookbook, but was almost identical, called for sour milk instead of sour cream, but I substituted the sour cream.
    Can’t wait to try with the ganache.

    1. Jamie says:

      I’m glad the recipe was such a hit with your book club. Thanks for stopping by!

      -Jamie

  7. Candace @ Cabot says:

    We’re all for anything that is this rich and chocolatey and sneaks in some veggies too. Great recipe!

    1. Jamie says:

      Thanks so much! I really appreciate you stopping by.

      -Jamie

  8. Veronica says:

    Is it possible to sub the eggs out with applesauce or banana?

    1. Jamie says:

      I think 1/4 cup of applesauce can be substituted for each egg. Thanks for stopping by.

      -Jamie

  9. Sandra says:

    Just what I was looking for! Thanks for the conversion, too!

  10. Joanna says:

    HI! Is it possible to substitute gluten free flour in this?

    1. Jamie says:

      Hi Joanna,
      I am not a gluten free baker, so I honestly have no idea. I would assume it would work okay, but it might be worth asking a gluten free blogger about the recipe.
      – Jamie