Easy Chocolate Zucchini Cake

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We’re about to head into the height of zucchini season, which is just one of the many reasons you’ll adore this Chocolate Zucchini Cake.

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.

Adding zucchini to cake happens to be one of my favorite ways to use the stuff. I also enjoy a good zucchini bread, like my Lemon Yogurt Zucchini Bread or my Chocolate Zucchini Bread.

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!

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.

This might just become your new favorite zucchini recipe!

Sprinkle of Science

How to Make Moist Chocolate Zucchini Cake

The Cocoa Powder

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.

Important: How to Shred Zucchini for Cake

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

1. 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.
2. 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.
3. Once you fold in the zucchini to the batter, stir gently until JUST combined. Over-mixing can cause a 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.
• Learn more about Butter vs. Oil in Baking here.

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!

What Type of Chocolate Chips Should I Use? 

I used semi-sweet chocolate chips, but you could experiment with milk chocolate chips, mini chocolate chips, or even white chocolate chips, if you prefer. Learn more about Chocolate in Baking here.

Is it Better to Bake a Cake in a Glass or Metal Pan?

• 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.
• Learn more about Glass vs. Metal Baking Pans in my article here. 

Frosting for Zucchini Cake

I used a simple icing for this Chocolate Zucchini Cake recipe, but you could also use my Cream Cheese Frosting, my delicious Chocolate Frosting, or my decadent Chocolate Ganache.

Can I Double this Recipe?

Yes! Double all ingredients, 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.

How Long Does Chocolate Zucchini Cake Last?

This Zucchini Cake can be stored in an airtight container at room temperature for up to 4 days.

Can You Freeze Chocolate Zucchini Cake?

• Freeze individual slices on parchment paper for about 15-30 minutes, then wrap each in plastic wrap and place in an airtight container.
• Defrost in the fridge or on the counter and let come to room temperature before enjoying.
• I recommend freezing the cake unfrosted.

How to Make

Easy Chocolate Zucchini Cake

By: Tessa Arias

4.94 from 199 votes

Yield: 9 cake squares

Prep Time: 20 minutes mins

Cook Time: 30 minutes mins

Review Print

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!

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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 fine sea 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

Instructions 

Make the cake:

• Preheat the oven to 350°F. Line an 8 by 8-inch metal baking pan* with parchment paper then spray with nonstick cooking spray.
• In a large bowl, whisk together the flour, cocoa, sugar, salt, and baking soda.
• In a small bowl, whisk together the melted butter, oil, sour cream, eggs, egg yolk, and vanilla extract.
• 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.
• Pour the batter into the prepared pan and bake for 30 minutes or until a toothpick or cake tester comes out clean. If your cake sinks slightly in the middle, that's normal because it's so moist and rich!
• Let cool completely.

Make the frosting:

• 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.
• Cake can be stored in an airtight container at room temperature for up to 4 days.

Show us!If you make this recipe, be sure to snap a picture and share it on Instagram with #handletheheat so we can all see!

Recipe Notes

* If using a glass pan, bake at 325°F for 35 to 40 minutes, or until a toothpick or cake tester comes out clean. 

Photos by Ashley McLaughlin.