Name: Chocolate Zucchini Cake Recipe
Prep time: 20 min
Cook time: 35 min
Total time: 55 min
Ingredients: 2 cups all purpose flour; 1 cup granulated sugar; 1 cup light brown sugar, packed; 1 cup unsweetened cocoa powder; 1 teaspoon baking soda; 1 teaspoon baking powder; 1 teaspoon fine sea salt; 1 teaspoon instant espresso powder; 3 large eggs, room temperature; 1 cup neutral oil, such as canola or avocado; 1 cup whole milk or buttermilk; 2 teaspoons pure vanilla extract; 2 cups shredded zucchini, packed (about 2 small or 1 large); 1 cup semisweet chocolate chips or chunks; 1/2 cup unsalted butter, softened; 1/2 cup unsweetened cocoa powder; 2 to 2 1/2 cups powdered sugar; 1/4 cup milk, plus more as needed; 1 teaspoon vanilla extract; 1 pinch salt

Chocolate Zucchini Cake Recipe tastes like a rich, fudgy brownie met a super moist snack cake and decided to become your new favorite dessert. It works for busy home bakers who want a chocolate cake that sneaks in veggies and takes about 1 hour start to finish. I have baked some version of this cake for a decade, and my kids still have no clue they eat zucchini in it.

Why Chocolate Zucchini Cake Recipe Is Worth It

This chocolate zucchini cake recipe gives you bakery-level flavor with simple pantry ingredients. The zucchini keeps the crumb soft and tender, so the cake stays moist for days without turning dense or gummy.

You mix the batter in one bowl, so cleanup stays easy. The recipe also forgives small measuring mistakes, which helps on hectic weeknights or when little helpers measure the flour.

Deep chocolate flavor, super moist crumb, and nobody guesses it has vegetables in it. ★★★★★

Ingredients You Need

Dry ingredients

2 cups all purpose flour
1 cup granulated sugar
1 cup light brown sugar, packed
1 cup unsweetened cocoa powder
1 teaspoon baking soda
1 teaspoon baking powder
1 teaspoon fine sea salt
1 teaspoon instant espresso powder, optional but boosts chocolate flavor

Use a good quality cocoa powder like Ghirardelli or Hershey Special Dark for deeper flavor. If you use Dutch process cocoa, keep the baking soda and baking powder amounts the same.

Wet ingredients

3 large eggs, room temperature
1 cup neutral oil, such as canola or avocado
1 cup whole milk or buttermilk
2 teaspoons pure vanilla extract

Oil keeps the cake soft and moist longer than butter. You can use half Greek yogurt and half milk if you want a slightly lighter crumb.

Zucchini and chocolate

2 packed cups shredded zucchini, about 2 small or 1 large
1 cup semisweet chocolate chips or chunks

Shred the zucchini on the small side of a box grater. Do not squeeze it dry, or the cake will lose moisture and turn dry.

Optional frosting

1 stick (1/2 cup) unsalted butter, softened
1/2 cup unsweetened cocoa powder
2 to 2 1/2 cups powdered sugar
1/4 cup milk, plus more as needed
1 teaspoon vanilla extract
Pinch of salt

You can skip the frosting and dust the cake with powdered sugar if you want a lighter dessert. Use any milk you have on hand, including oat or almond milk.

Equipment list

9 by 13 inch baking pan, metal or glass
Large mixing bowl
Medium mixing bowl
Whisk and rubber spatula
Box grater for zucchini
Measuring cups and spoons
Cooling rack
Hand mixer or stand mixer for frosting, optional

Quick Tips & substitutions

Use small to medium zucchini, since large ones hold more water and seeds.
Leave the zucchini unpeeled, because the peel adds color and you will not taste it.
Do not squeeze out the zucchini unless it drips heavily; gentle blotting with a towel works fine.
Mix the batter until just combined to keep the crumb tender.
Swap half the oil with unsweetened applesauce if you want a slightly lighter cake.
Use coconut sugar in place of brown sugar if you prefer less refined sugar.
Replace instant espresso powder with strong instant coffee or skip it if you avoid caffeine.
Use dairy free milk and dairy free chocolate chips to support a dairy free version.
Line the pan with parchment for easy removal and cleaner slices.
Let the cake cool fully before frosting so the frosting does not melt and slide.

How to Make Chocolate Zucchini Cake Recipe

Step 1: Prep the pan and oven

Preheat your oven to 350°F. Grease a 9 by 13 inch pan with oil or butter, then lightly dust it with cocoa powder so the cake does not stick. Set the pan aside while you mix the batter.

Step 2: Shred the zucchini

Wash and dry the zucchini. Trim the ends, then shred it on the small holes of a box grater. Lightly blot the shredded zucchini with a clean towel if it looks very wet, then measure 2 packed cups and set aside.

Step 3: Mix the dry ingredients

In a large bowl, whisk together flour, granulated sugar, brown sugar, cocoa powder, baking soda, baking powder, salt, and instant espresso powder. Break up any cocoa or brown sugar clumps with the whisk. Make sure the mixture looks evenly combined and uniform in color.

Step 4: Mix the wet ingredients

In a separate medium bowl, whisk the eggs until smooth. Add oil, milk, and vanilla, then whisk until the mixture looks fully combined and slightly creamy. This step helps the eggs blend evenly into the batter.

Step 5: Combine wet and dry

Pour the wet mixture into the bowl with the dry ingredients. Gently whisk or stir with a spatula until you no not see streaks of dry flour. Scrape the sides and bottom of the bowl so no dry pockets hide under the batter.

Step 6: Fold in zucchini and chocolate

Add the shredded zucchini and chocolate chips to the bowl. Fold them in with a spatula until they spread evenly through the batter. The batter will look thick and glossy with plenty of visible zucchini strands.

Step 7: Bake the cake

Pour the batter into the prepared pan and spread it into an even layer. Tap the pan lightly on the counter to pop any large air bubbles. Bake for 30 to 35 minutes, until a toothpick inserted in the center comes out with a few moist crumbs.

Step 8: Cool the cake

Place the pan on a cooling rack. Let the cake cool in the pan for at least 30 to 45 minutes before frosting or slicing. The cake sets as it cools, so it slices more cleanly and keeps its shape.

Step 9: Make the chocolate frosting

In a medium bowl, beat the softened butter with a hand mixer until creamy. Add cocoa powder and mix until smooth. Add powdered sugar, milk, vanilla, and salt, then beat until the frosting turns fluffy and spreadable, adding a splash more milk if it looks too thick.

Step 10: Frost and serve

Spread the frosting over the cooled chocolate zucchini cake in an even layer. Sprinkle extra chocolate chips or shaved chocolate on top if you want more texture. Slice into squares and serve at room temperature.

Recipe Variations

Gluten free: Use a 1 to 1 gluten free baking flour blend and check that your cocoa and chocolate chips list gluten free on the label.
Vegan: Use flax eggs or a commercial egg replacer, dairy free milk, and dairy free chocolate chips; frost with a vegan butter based frosting.
Low carb: Use a low carb sweetener that measures like sugar and a lower carb flour blend; expect a slightly different texture.
Extra chocolate: Stir in 1/2 cup mini chocolate chips in addition to the regular chips for a double chocolate zucchini cake.
Nutty crunch: Add 1/2 to 3/4 cup chopped walnuts or pecans to the batter.
Spiced version: Add 1 teaspoon ground cinnamon and a pinch of nutmeg for a warm, cozy flavor.
Cupcakes: Portion the batter into lined muffin tins and bake about 18 to 22 minutes for chocolate zucchini cupcakes.

Ways to Serve

Serve plain with a cold glass of milk or your favorite non dairy milk.
Add a scoop of vanilla or chocolate ice cream on warm slices.
Top with fresh berries and a light dusting of powdered sugar.
Pack slices in lunchboxes as a sweet surprise.
Cut into small squares and serve as a potluck dessert tray.

Storage Success

Let the chocolate zucchini cake cool completely before you cover it, so condensation does not make the top soggy. Store the cake tightly covered at room temperature for up to 3 days, or refrigerate it for up to 5 days. If you stack slices, place parchment between layers so they do not stick. Freeze individual slices in airtight containers for up to 2 months, then thaw at room temperature when a chocolate craving hits.