Homemade Zucchini Brownies With Walnuts

I never thought I’d be sneaking vegetables into my brownies, but here we are – and trust me, these fudgy chocolate squares packed with shredded zucchini and crunchy walnuts are absolute perfection. The zucchini keeps them incredibly moist without adding any veggie flavor, while the walnuts give you that satisfying bite in every piece. I’ve been making these on repeat all summer, and they disappear faster than regular brownies at my house!

Estimated Nutrition

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

• Calories: 3400-3700
• Protein: 40-50 g
• Fat: 180-200 g
• Carbohydrates: 440-480 g

Ingredients

For the batter base:

• 6 oz chocolate (I prefer Ghirardelli 60% cacao bittersweet chips for melting)
• 1/4 cup olive oil
• 1/2 cup butter (I like Kerrygold unsalted butter for this)
• 1 cup brown sugar
• 1 cup sugar
• 3 eggs (room temperature, about 70°F)
• 1 egg yolk
• 1 tablespoon vanilla essence

For the dry ingredients:

• 1 1/8 cups flour (I always use King Arthur all-purpose flour)
• 1/2 cup cocoa
• 1 tsp baking soda
• 1 1/4 tsp salt
• 1/2 tsp baking powder
• 1/4 tsp cinnamon
• 1/8 tsp ground nutmeg
• 1 1/2 tsp espresso powder (helps intensify the chocolate flavor)

For the inclusions:

• 2 cups zucchini (finely shredded and squeezed dry to remove excess moisture)
• 3/4 cup walnuts (roughly chopped into 1/4-inch pieces)

Step 1: Prepare Pan and Preheat Oven

Preheat your oven to 350°F.

While it heats, line a 9x13 inch baking dish with parchment paper, allowing it to overhang slightly on two sides for easy removal later, then lightly grease the parchment and bottom of the pan.

This setup ensures your brownies won't stick and makes cooling and cutting much easier.

Step 2: Prepare Zucchini and Combine Dry Ingredients

• 2 cups zucchini
• 1 1/8 cups flour
• 1/2 cup cocoa
• 1 tsp baking soda
• 1 1/4 tsp salt
• 1/2 tsp baking powder
• 1/4 tsp cinnamon
• 1/8 tsp ground nutmeg
• 1 1/2 tsp espresso powder

Finely shred your zucchini and place it in a clean kitchen towel or cheesecloth, then squeeze firmly to remove as much excess moisture as possible—this is crucial for preventing overly dense or soggy brownies.

While you're working on the zucchini, in a medium bowl whisk together the flour, cocoa powder, baking soda, salt, baking powder, cinnamon, nutmeg, and espresso powder.

I like to whisk these dry ingredients thoroughly so the espresso powder distributes evenly and intensifies the chocolate flavor throughout the brownies.

Step 3: Melt Chocolate and Fats

• 6 oz chocolate chips
• 1/4 cup olive oil
• 1/2 cup butter

In a medium saucepan over low to medium-low heat, combine the olive oil, butter, and chocolate chips.

Stir frequently for about 5 minutes until everything is melted and smooth—keeping the heat low prevents the chocolate from scorching and ensures a silky texture.

Remove from heat and let cool for 1-2 minutes before proceeding to the next step.

Step 4: Build the Wet Batter Base

• melted chocolate mixture from Step 3
• 1 cup brown sugar
• 1 cup sugar
• 3 eggs
• 1 egg yolk
• 1 tablespoon vanilla essence

To the melted chocolate mixture, stir in the brown sugar and sugar until well combined.

Remove from heat and let cool slightly for about 1 minute.

Add the 3 room-temperature eggs one at a time, stirring well after each addition to prevent any scrambling, then stir in the egg yolk and vanilla essence until fully incorporated.

Room-temperature eggs incorporate more smoothly and create a better emulsion with the chocolate and fats.

Step 5: Combine Wet and Dry Ingredients

• wet batter mixture from Step 4
• dry ingredient mixture from Step 2

Pour the wet batter from Step 4 into the bowl with the dry ingredient mixture from Step 2 and stir until just combined—don't overmix, as this can develop gluten and make the brownies tough.

The batter should look thick and fudgy with no visible streaks of flour.

Step 6: Fold in Zucchini, Walnuts, and Bake

• zucchini and walnut mixture
• 2 cups zucchini
• 3/4 cup walnuts

Gently fold the squeezed-dry zucchini and chopped walnuts into the batter using a spatula, being careful not to overmix.

Pour the batter into your prepared baking dish from Step 1 and spread it evenly.

Bake for 30 to 40 minutes, until a toothpick inserted into the center comes out with just a few moist crumbs—slightly underbaking keeps these brownies fudgy and tender.

Let cool in the pan for 5 minutes before lifting out using the parchment overhang and cutting into squares.

Homemade Zucchini Brownies With Walnuts

Delicious Homemade Zucchini Brownies With Walnuts recipe with step-by-step instructions.

Print Recipe Pin Recipe

Prep Time 20 minutes mins

Cook Time 40 minutes mins

Total Time 1 hour hr

Servings: 18 pieces

Calories: 3550

Ingredients Method

Ingredients

  

For the batter base

• 6 oz chocolate (I prefer Ghirardelli 60% cacao bittersweet chips for melting)
• 1/4 cup olive oil
• 1/2 cup butter (I like Kerrygold unsalted butter for this)
• 1 cup brown sugar
• 1 cup sugar
• 3 eggs (room temperature, about 70°F)
• 1 egg yolk
• 1 tablespoon vanilla essence

For the dry ingredients

• 1 1/8 cups flour (I always use King Arthur all-purpose flour)
• 1/2 cup cocoa
• 1 tsp baking soda
• 1 1/4 tsp salt
• 1/2 tsp baking powder
• 1/4 tsp cinnamon
• 1/8 tsp ground nutmeg
• 1 1/2 tsp espresso powder (helps intensify the chocolate flavor)

For the inclusions

• 2 cups zucchini (finely shredded and squeezed dry to remove excess moisture)
• 3/4 cup walnuts (roughly chopped into 1/4-inch pieces)

Method

 

1. Preheat your oven to 350°F. While it heats, line a 9x13 inch baking dish with parchment paper, allowing it to overhang slightly on two sides for easy removal later, then lightly grease the parchment and bottom of the pan. This setup ensures your brownies won't stick and makes cooling and cutting much easier.
2. Finely shred your zucchini and place it in a clean kitchen towel or cheesecloth, then squeeze firmly to remove as much excess moisture as possible—this is crucial for preventing overly dense or soggy brownies. While you're working on the zucchini, in a medium bowl whisk together the flour, cocoa powder, baking soda, salt, baking powder, cinnamon, nutmeg, and espresso powder. I like to whisk these dry ingredients thoroughly so the espresso powder distributes evenly and intensifies the chocolate flavor throughout the brownies.
3. In a medium saucepan over low to medium-low heat, combine the olive oil, butter, and chocolate chips. Stir frequently for about 5 minutes until everything is melted and smooth—keeping the heat low prevents the chocolate from scorching and ensures a silky texture. Remove from heat and let cool for 1-2 minutes before proceeding to the next step.
4. To the melted chocolate mixture, stir in the brown sugar and sugar until well combined. Remove from heat and let cool slightly for about 1 minute. Add the 3 room-temperature eggs one at a time, stirring well after each addition to prevent any scrambling, then stir in the egg yolk and vanilla essence until fully incorporated. Room-temperature eggs incorporate more smoothly and create a better emulsion with the chocolate and fats.
5. Pour the wet batter from Step 4 into the bowl with the dry ingredient mixture from Step 2 and stir until just combined—don't overmix, as this can develop gluten and make the brownies tough. The batter should look thick and fudgy with no visible streaks of flour.
6. Gently fold the squeezed-dry zucchini and chopped walnuts into the batter using a spatula, being careful not to overmix. Pour the batter into your prepared baking dish from Step 1 and spread it evenly. Bake for 30 to 40 minutes, until a toothpick inserted into the center comes out with just a few moist crumbs—slightly underbaking keeps these brownies fudgy and tender. Let cool in the pan for 5 minutes before lifting out using the parchment overhang and cutting into squares.