Easy Chocolate Zucchini Cake

By Tessa Arias
  |  
October 7th, 2021
4.94 from 176 votes
4.94 from 176 votes

Ultra rich, moist, and fudgy Easy Chocolate Zucchini Cake is the perfect summer treat for any chocoholic and can be made in less than 1 hour! No mixer required. Tons of chocolate flavor!

Yield: 9 cake squares

Prep Time: 20 minutes

Cook: 30 minutes

Tessa's Recipe Rundown...

Taste: Ultra chocolaty! I doubt any kids would guess there’s a vegetable involved here.
Texture:  Rich, fudgy, and moist.
Ease: Super quick and easy. No mixer, no assembling, no decorating.
Pros: Simple summer treat!
Cons: None 🙂
Would I make this again? Absolutely, all season long.

We’re about to head into the height of zucchini season which I’m so excited about!

I love getting fresh zucchini from the farmer’s market all summer long. It’s one of those veggies that’s so easy to cook and bake with. You can find a million ways to get creative whether you’re going savory or sweet. And it doesn’t take nearly an hour to cook like root veggies.

Zucchini Cake with Chocolate and a simple icing on top

Adding zucchini into cake happens to be one of my favorite ways to use the stuff.

I love snack cakes like this recipe because’ they’re just one layer and there’s no assembly or decorating required. They’re also super easy to transport. You don’t even need an electric mixer for the batter or the icing here.

That makes this recipe perfect for bringing to a summer potluck or BBQ. Especially if you have an abundance of zucchini to use up!

Easy Chocolate Zucchini Cake cut into squares

I find many chocolate zucchini cakes to be kind of bland and a little dry. Read my tips below for getting a super rich and fudgy cake with tons of chocolate flavor.

How to Make Moist Chocolate Zucchini Cake

Cocoa Powder in Chocolate Cake

Cocoa powder lends more chocolate flavor than melted chocolate. But it can also zap some moisture, so read my tips below for how to make sure your cake is nice and tender and moist. This recipe uses natural unsweetened cocoa powder (not Dutch process cocoa powder). Learn more about cocoa powder here.

For best results, weigh your cocoa powder and flour to ensure you don’t over measure. This will result in a dry cake. If you don’t have a digital kitchen scale, then use the spoon-and-level method.

How to Prepare Zucchini for Cake (IMPORTANT!)

To avoid gummy, dense, or unbaked cake it’s important to remove as much excess water from the zucchini as possible.

Start by washing the zucchini and trimming the ends. Grate using the big holes of a box grater. Scoop up the shredded zucchini and place in a strainer or colander. Move on to prepare the rest of the ingredients and batter for the recipe.

Once you’re ready to add in the zucchini, wrap it in a clean towel or paper towels and give it a very tight squeeze with your hands to wring out excess water. Do this a few times. If your hands aren’t quite strong enough you can also press the zucchini inside a potato ricer or hand held citrus squeezer. This is super effective at getting rid of water.

Once you add the zucchini to the batter, stir gently until JUST combined. Over-mixing can cause tough or gummy texture.

Why use butter AND oil in a cake?

I find this provides the best of both worlds. You get the wonderful flavor from the butter and the moist texture from the oil. This is because oil is a liquid at room temperature so it gives your palate the sensation of moisture. If you don’t have oil you can use 1 stick (113 grams) of butter for all the fat in the recipe.

How to Bake a Moist & Fudgy Chocolate Cake

In addition to the tips above, using ingredients like brown sugar, full fat sour cream, and an extra egg yolk all help to add richness and moisture to this cake. That’s because these ingredients both tenderize and draw and hold onto moisture. You can learn more about how baking ingredients work in my Magic of Baking online class.

Can I substitute the sour cream?

You can use full fat plain yogurt instead!

Metal vs. Glass Baking Pans

This recipe is best baked in an 8-inch metal baking pan. Metal conducts heat more quickly and efficiently than glass or ceramic so you won’t have any issues with an under-baked center. If you must use glass or ceramic, reduce the baking temperature to 325°F and increase the baking time by 5 to 10 minutes.

Can I double this recipe?

Yes! Double all ingredients and bake in a 9 by 13-inch pan and add about 5 to 10 minutes to the baking time. If using glass see note above.

Piece of chocolate zucchini snack cake on a plate with a fork

More Chocolate Cake Recipes

4.94 from 176 votes

How to make
Easy Chocolate Zucchini Cake

Yield: 9 cake squares
Prep Time: 20 minutes
Cook Time: 30 minutes
Ultra rich, moist, and fudgy Easy Chocolate Zucchini Cake is the perfect summer treat for any chocoholic and can be made in less than 1 hour! No mixer required. Tons of chocolate flavor!

Ingredients

For the cake:

  • 1 cup plus 2 tablespoons (143 grams) all-purpose flour, measured correctly
  • 1/2 cup (43 grams) unsweetened cocoa, measured correctly
  • 1 cup (200 grams) light brown sugar
  • 1 teaspoon salt
  • 1 teaspoon baking soda
  • 4 tablespoons (57 grams) unsalted butter, melted
  • 1/4 cup fresh vegetable oil
  • 1/2 cup (120 grams) full fat sour cream or plain whole milk yogurt, at room temperature
  • 2 large eggs plus 1 egg yolk, at room temperature
  • 2 teaspoons vanilla extract
  • 1 cup (136 grams) shredded zucchini, from about 1 medium zucchini
  • 1 cup (170 grams) semisweet chocolate chips

For the icing:

  • 1/2 cup (63 grams) powdered sugar, sifted
  • 1 tablespoon milk

Directions

Make the cake:

  1. Preheat the oven to 350°Line a 8 by 8-inch metal baking pan with parchment paper then spray with nonstick cooking spray. If using a glass pan, heat the oven to 325°F.

  2. In a large bowl, whisk together the flour, cocoa, sugar, salt, and baking soda.
  3. In a small bowl whisk together the melted butter, oil, sour cream, eggs, egg yolk, and vanilla extract.
  4. Make a well in the center of the dry ingredients and pour in the wet ingredients. Stir until a few streaks of flour remain. Squeeze out any additional moisture from the shredded zucchini before adding to the batter. See recipe post for tips on reducing excess moisture, which will create a gummy cake texture. Add in the chocolate chips. Stir until just barely combined.

  5. Pour the batter into the prepared pan and bake for 30 minutes (35 to 40 minutes if using glass) or until a cake tester comes out clean. If your cake sinks slightly in the middle, that's normal because it's so moist and rich!

  6. Let cool completely.

Make the frosting:

  1. In a medium bowl stir together the sugar and milk with a fork until smooth and thick but pourable. Drizzle all over the cake. Let set before serving.
  2. Cake can be stored in an airtight container at room temperature for up to 4 days.

Recipe Video

Course: Dessert
Cuisine: American
Keyword: summer

Photos by Ashley McLaughlin.

August 2020 Baking Challenge

This recipe was the selection for the August 2020 baking challenge! See the entries below Join the current monthly challenge here.

Tessa Arias

About Tessa...

I share trusted baking recipes your friends will LOVE alongside insights into the science of sweets. I'm a professionally trained chef, cookbook author, and cookie queen. I love to write about all things sweet, carb-y, and homemade. I live in Phoenix, Arizona (hence the blog name!)

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Recipe Rating




  1. #
    Susan M — December 14, 2021 at 10:24 pm

    Can some left over baked cake be frozen for future consumption?

    • #
      Emily — December 15, 2021 at 11:35 am

      Hi Susan! We haven’t tried that, but it should be ok (though maybe not as pretty)! I’d recommend freezing individual slices on parchment for about 15-30 minutes, then wrapping each in plastic wrap and placing in an airtight container. Defrost in the fridge or on the counter and let come to room temp before enjoying.

  2. #
    Susan M — December 14, 2021 at 10:22 pm

    I just left a comment, but forgot to rate it. It gets all 5 stars from me

  3. #
    Susan M — December 14, 2021 at 10:18 pm

    I loved this Zucchini recipe. I have had breads made with zucchini and found them to be a little bland. I used a 8×8 Pyrex glass pan and sprayed it with some Pam. As another comment that was left, I passed on the icing and just used some powdered confectioners sugar more for presentation than for extra sweetness. It was a big hit and I enjoyed sharing it with several friends to enjoy. This will remain as a favorite go to recipe for me. Thank You

    • #
      Emily — December 15, 2021 at 11:36 am

      So happy you loved this recipe, Susan, and that it’s a go to! Thanks for sharing your tweaks as well 🙂

  4. #
    Brandice Hamlett — December 11, 2021 at 10:52 pm

    This is a great recipe! But this week I learned that it can also be a great base if needed for dairy and gluten free. I substituted plant based butter and sour cream, allergy friendly chocolate chips, and Bob’s Red Mill Gluten Free All Purpose flour. I did mini-cupcakes baked for 14 minutes. They were absolutely beautiful! Fluffy, moist, and so delicious. The zucchini helps bond the flour so they doesn’t fall apart, and it also removed grittiness that often comes along with gluten free products. Served them at a party and no one even realized it was zucchini cake. They were demolished so quickly and no one could believe they were really DF/GF.

    Thanks so much for the yummy recipe! Especially love the weights that prevent user error on this recipe!

    • #
      Emily — December 13, 2021 at 3:20 pm

      Thanks so much for sharing your findings! Glad this recipe worked perfectly with your substitutions 🙂

  5. #
    Bonnie M — October 5, 2021 at 6:53 pm

    Cake is delicious…moist. You do not taste the zucchini at all. I did not have vanilla extract and used almond extract and it worked great!

    • #
      Emily — October 6, 2021 at 9:09 am

      So happy you enjoyed this recipe, Bonnie!

  6. #
    Janet — September 9, 2021 at 4:06 am

    I came across this recipe when looking for a new recipe to bake with zucchini. I have made this twice now in 3 weeks. My family loves it. The chocolate flavor is so intense. The cake is so moist. It is an exceptional recipe and so easy to make. I love the fact that it is only an 8 x 8 one pan cake.

    • #
      Emily — September 9, 2021 at 12:07 pm

      Amazing!! So happy to hear how much you’re enjoying this recipe and that it’s a family hit! Thanks for the comment, Janet 🙂

  7. #
    alissa — September 6, 2021 at 2:13 pm

    I have made this delicious cake for multiple family gatherings this summer and it has always been a hit! I double the recipe and bake it in a 9×13 cake pan, and I modified the recipe slightly – I use 275 g. sugar instead of 400 g., fat-free plain Greek yogurt instead of sour cream, and 2 eggs + 3 Tbsp. ground flax mixed with 9 Tbsp. water (allow to gel in the fridge for ~10 mins.) instead of 4 eggs and 2 egg yolks. My family likes desserts on the slightly less-sweet side, so I only use 170 g. of chocolate chips for a double recipe. I have gotten rave reviews every time 🙂

    • #
      alissa — September 6, 2021 at 2:23 pm

      also i skip the icing because i don’t think it’s necessary – even with a reduced amount of sugar, this cake is plenty sweet! it is very yummy served with a spoonful of plain Greek yogurt and a few extra chocolate chips sprinkled on top!

    • #
      Emily — September 7, 2021 at 4:00 pm

      So happy to hear your substitutions worked well, thanks for letting us know!

  8. #
    Sarah Brooks — August 30, 2021 at 1:37 pm

    THE BEST! The zucchini disappears and it turns into a rich, moist, chocolate cake. And super easy to make. I would recommend to anyone, and will be making this again and again.

    • #
      Emily — August 31, 2021 at 8:15 am

      YAY! So glad to hear it, Sarah! Thanks for the rave review 🙂

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