Best Double Chocolate Zucchini Brownies

I’ve been sneaking zucchini into desserts for years, but these double chocolate zucchini brownies might be my greatest achievement yet. They’re incredibly fudgy thanks to real butter and chopped chocolate, and the shredded zucchini keeps them moist without adding any veggie flavor whatsoever. Trust me, even the pickiest eaters in your life won’t guess there’s a green vegetable hiding in these rich, chocolatey treats!

Estimated Nutrition

Estimated nutrition for the whole recipe (without optional ingredients):

• Calories: 3700-3950
• Protein: 32-36 g
• Fat: 220-235 g
• Carbohydrates: 440-470 g

Ingredients

For the brownie batter:

• 3/4 cup butter (I like Kerrygold unsalted butter for this)
• 1 cup chocolate (chopped into 1/2-inch pieces)
• 1/3 cup cocoa powder (sifted to remove lumps)
• 1/2 cup brown sugar
• 1 cup sugar
• 1 1/2 tsp vanilla
• 1 tsp espresso powder
• 1 egg yolk (room temperature, about 70°F)
• 1 tsp baking soda
• 1 tsp salt
• 2 1/4 cups zucchini (shredded and squeezed dry to remove excess moisture)
• 1 1/8 cups flour (I always use King Arthur all-purpose flour)
• 1 cup chocolate chips

For the topping:

• 1 cup chocolate chips (I use Ghirardelli semi-sweet chips)
• 1/4 teaspoon flaky sea salt

Step 1: Prepare Your Pan and Preheat the Oven

Preheat your oven to 350°F and grease a 9x13 inch baking dish (or similar size) with butter or non-stick spray.

I like to use parchment paper in addition to greasing—it makes removing the brownies so much easier and ensures clean edges.

Step 2: Melt the Chocolate and Butter Base

• 3/4 cup butter
• 1 cup chocolate
• 1/3 cup cocoa powder

Combine the butter, chopped chocolate, and sifted cocoa powder in a heat-safe bowl and melt together gently.

You can do this in the microwave in 30-second intervals, stirring between each one, or over a double boiler for more control.

Stir until completely smooth—this creates the rich chocolate foundation for your brownies.

I find that having the chocolate pieces small and uniform helps them melt evenly without any lumps.

Step 3: Build the Wet Mixture with Sugar and Eggs

• melted chocolate mixture from Step 2
• 1/2 cup brown sugar
• 1 cup sugar
• 1 1/2 tsp vanilla
• 1 egg yolk

Stir the brown sugar, white sugar, vanilla, and room-temperature egg yolk into the melted chocolate mixture from Step 2.

Mix thoroughly until the sugars are fully incorporated and the mixture is smooth.

The room-temperature egg yolk integrates better than a cold one, creating a more cohesive batter.

Step 4: Combine Dry Ingredients with Zucchini

• wet mixture from Step 3
• 1 tsp baking soda
• 1 tsp salt
• 2 1/4 cups zucchini

In a separate small bowl, whisk together the baking soda and salt.

Add this to the wet mixture from Step 3 and stir well.

Now fold in the shredded and squeezed-dry zucchini until evenly distributed throughout the batter.

The zucchini adds moisture and texture while keeping these brownies tender—squeezing out the excess water is crucial so your brownies don't become soggy.

Step 5: Finish the Batter and Fill the Pan

• batter from Step 4
• 1 1/8 cups flour
• 1 cup chocolate chips
• 1 cup chocolate chips
• 1/4 teaspoon flaky sea salt

Gently fold the flour into the batter from Step 4 until just combined—don't overmix, as this can lead to dense brownies.

Fold in 1 cup of chocolate chips.

Pour the batter into your prepared pan from Step 1 and smooth the top with a spatula.

Scatter the remaining 1 cup of chocolate chips evenly over the top, then sprinkle with the flaky sea salt for a subtle contrast that enhances the chocolate flavor.

Step 6: Bake and Cool

Bake for 25-30 minutes, until a toothpick inserted into the center comes out with just a few moist crumbs—don't overbake or you'll lose the fudgy texture.

Remove from the oven and let the brownies cool completely in the pan before cutting.

This resting time allows the crumb structure to set properly, giving you clean, beautiful slices.

Best Double Chocolate Zucchini Brownies

Delicious Best Double Chocolate Zucchini Brownies recipe with step-by-step instructions.

Print Recipe Pin Recipe

Prep Time 15 minutes mins

Cook Time 30 minutes mins

Total Time 45 minutes mins

Servings: 15 servings

Calories: 3825

Ingredients Method

Ingredients

  

For the brownie batter

• 3/4 cup butter (I like Kerrygold unsalted butter for this)
• 1 cup chocolate (chopped into 1/2-inch pieces)
• 1/3 cup cocoa powder (sifted to remove lumps)
• 1/2 cup brown sugar
• 1 cup sugar
• 1 1/2 tsp vanilla
• 1 tsp espresso powder
• 1 egg yolk (room temperature, about 70°F)
• 1 tsp baking soda
• 1 tsp salt
• 2 1/4 cups zucchini (shredded and squeezed dry to remove excess moisture)
• 1 1/8 cups flour (I always use King Arthur all-purpose flour)
• 1 cup chocolate chips

For the topping

• 1 cup chocolate chips (I use Ghirardelli semi-sweet chips)
• 1/4 teaspoon flaky sea salt

Method

 

1. Preheat your oven to 350°F and grease a 9x13 inch baking dish (or similar size) with butter or non-stick spray. I like to use parchment paper in addition to greasing—it makes removing the brownies so much easier and ensures clean edges.
2. Combine the butter, chopped chocolate, and sifted cocoa powder in a heat-safe bowl and melt together gently. You can do this in the microwave in 30-second intervals, stirring between each one, or over a double boiler for more control. Stir until completely smooth—this creates the rich chocolate foundation for your brownies. I find that having the chocolate pieces small and uniform helps them melt evenly without any lumps.
3. Stir the brown sugar, white sugar, vanilla, and room-temperature egg yolk into the melted chocolate mixture from Step 2. Mix thoroughly until the sugars are fully incorporated and the mixture is smooth. The room-temperature egg yolk integrates better than a cold one, creating a more cohesive batter.
4. In a separate small bowl, whisk together the baking soda and salt. Add this to the wet mixture from Step 3 and stir well. Now fold in the shredded and squeezed-dry zucchini until evenly distributed throughout the batter. The zucchini adds moisture and texture while keeping these brownies tender—squeezing out the excess water is crucial so your brownies don't become soggy.
5. Gently fold the flour into the batter from Step 4 until just combined—don't overmix, as this can lead to dense brownies. Fold in 1 cup of chocolate chips. Pour the batter into your prepared pan from Step 1 and smooth the top with a spatula. Scatter the remaining 1 cup of chocolate chips evenly over the top, then sprinkle with the flaky sea salt for a subtle contrast that enhances the chocolate flavor.
6. Bake for 25-30 minutes, until a toothpick inserted into the center comes out with just a few moist crumbs—don't overbake or you'll lose the fudgy texture. Remove from the oven and let the brownies cool completely in the pan before cutting. This resting time allows the crumb structure to set properly, giving you clean, beautiful slices.