Easy Chocolate Zucchini Cake

Recipe By Tessa Arias
  |  
June 18th, 2019
4.95 from 18 votes
4.95 from 18 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

August 2020 Baking Challenge

This recipe is the selection for the current monthly baking challenge! Bake a batch, snap a photo, and upload it below for a chance to win prizes. See all challenge details here.

August 2020 Baking Challenge

4.95 from 18 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.
Course: Dessert
Cuisine: American
Keyword: summer

Photos by Ashley McLaughlin.

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. #
    Jennifer Wiseman — June 21, 2019 at 6:49 pm

    I often have shredded zucchini in the freezer. Based on your description, it sounds like it wouldn’t be usable in this recipe. Any thoughts?

    • #
      Tessa Arias — June 26, 2019 at 5:39 pm

      I would thaw and then *really* try to remove as much excess moisture from the zucchini as possible before baking with it!

  2. #
    Juditta — July 4, 2019 at 1:08 am

    Very tasty. Easy to make

  3. #
    Kim — August 31, 2019 at 8:34 pm

    This cake was phenomenal! Super moist! Doubled the recipe. Took about 45 minutes to bake.

  4. #
    Jemima — February 14, 2020 at 1:25 am

    This turned out to be a hit in my house so it will be made a few more times as I’m loaded with zucchini that I’ve grown and they ain’t little lol and still got heaps more growing so always looking for more recipes thanks heaps for this great.

  5. #
    Dani — April 24, 2020 at 2:23 am

    Delicious and easy, my family and I loved it.

  6. #
    Morgan M — May 5, 2020 at 8:15 am

    This recipe is amazing. The cake is moist, rich, and flavorful. I didn’t even have to put the icing on as there was enough deliciousness in the cake itself! So easy to make and will be baking again!

  7. #
    Kerri C — May 17, 2020 at 5:06 pm

    Quick easy to follow recipe Was delicious & stayed moist. Will definitely be making again soon !

  8. #
    Mandy — July 2, 2020 at 6:49 pm

    I just made this today!!! I’m pregnant and had a chocolate craving after seeing this on Tessa’s Instagram earlier in the week. The recipe is pretty easy to make. We julienned and chopped our zucchini since we don’t have a grater…hah!!

    I had to bake for about 35 minutes instead of 30 minutes, however I may have sent my temperature slightly under 350°, since my oven usually runs hot.

    Overall, easy recipe and REALLY tasty!

  9. #
    Faith — July 10, 2020 at 10:31 am

    If you love CHOCOLATE you will love this! It is very good tasting, moist, and easy to make! But man is it CHOCOLATE! You will need a glass of milk or some ice-cream to help calm down all that CHOCOLATE flavor!

  10. #
    Aaron Hockstein — August 1, 2020 at 6:18 pm

    Loved it! Extremely moist and super easy.

  11. #
    Martin — August 1, 2020 at 10:47 pm

    Really super delicious! I followed the recipe exactly and it came out perfect. I will definitely make it again, and I think it would really nice with the addition of some nuts.

  12. #
    Cindy :-) — August 2, 2020 at 11:17 am

    Soooo incredible. So moist and satisfying. Plan a double batch. This will now be my chocolate go to! And because it’s got zucchini in the batter there is zero guilt. Lol. Baked 15 squares using the Pampered Chef 12 square baking pan (baked 8 minutes). This is now at the top of my favorite Tessa recipes.

  13. #
    Marguerite — August 2, 2020 at 7:03 pm

    Easy to make and very delicious. Moist and chocolaty. Great use for the abundance of zucchini this time of year! My family loved it.

  14. #
    Nadine — August 3, 2020 at 12:16 pm

    I will be testing out this recipe!!! Can’t wait… but I’ve got to get the magic ingredient- the Zucchini ofc.

  15. #
    Alan Morlan — August 3, 2020 at 12:16 pm

    This is probably a rookie dumb question, but…can i cheat and use the zucchini noodles available at the grocery store? Maybe cut them into pieces?

    Thank you,
    Alan Morlan

  16. #
    sophia cheung — August 3, 2020 at 2:15 pm

    I’ve made this twice in a week, so satisfying. Rich, moist and chocolaty piece of heaven.

  17. #
    Cassie — August 3, 2020 at 2:26 pm

    Love how quick and easy this recipe comes together! And of course it’s delicious!

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