This post may contain affiliate links. Please read our disclosure policy.
I tested three versions of these zucchini brownies to get them just right—chewy, fudgy, and never dry. Topped with a classic crackly frosting, they’re a home baker’s dream dessert.
Chocolate Brownies with Zucchini
When I set out to create the perfect zucchini brownies, I started with my tried-and-true homemade brownie recipe as the foundation. The first test batch, after adding shredded zucchini, turned out so dry. The flavor was there, but they lacked that irresistible chewy texture I demand from a brownie. I knew I could do better.
To fix the dryness, I reduced the flour and tried adding hot water to bloom the cocoa powder for a richer flavor.
The result? A luscious, pudding-like brownie that was so decadent but lacked any real structure. Back to the mixing bowl I went.
For the third round, I brought back the original flour amount, omitted the water, reduced the chocolate by just one ounce, and added an extra egg to give the brownies the structure they needed without losing moisture. That third test was the winner, fudgy, moist, and perfectly chewy.
Because I’m me, I wasn’t done there.
I polled my Instagram audience on whether zucchini brownies deserved frosting, 52% voted yes. Challenge accepted.
I topped a batch with my old-school boil-and-set frosting that hardens into a glossy, slightly crackly layer as it cools. OMG. Game changer.
It’s the ultimate finish to these rich, secretly veggie-packed brownies. Every step of this recipe has been tested (and re-tested!) so you don’t have to wonder if it’ll work. It does. And you’re going to love them.
Why You’ll Love These Zucchini Brownies
- Fudgy, never dry: The zucchini adds moisture without weighing down the brownies, giving you that soft, chewy texture every brownie lover craves.
- Bakery-worthy flavor: A mix of melted chocolate and cocoa powder creates deep, rich chocolate flavor in every bite.
- Crackly frosting upgrade: My nostalgic boil-and-set frosting sets into a glossy, slightly firm layer that’s the perfect contrast to the soft brownie underneath.
- Proven recipe testing: After three rounds of testing, I found the perfect balance of flour, chocolate, and egg, so you don’t have to guess what will work.
- Beginner-friendly: No fancy tools or techniques are required—just simple steps that work every time.
Ingredients You’ll Need
These zucchini brownies are made with simple pantry staples, but every ingredient plays a key role in creating that fudgy, rich texture.
- All-purpose flour: The structure builder. Measuring by weight ensures your brownies are never dry or dense.
- Salt
- Baking soda: A touch of lift keeps the brownies from being too heavy while still maintaining that fudgy texture.
- Natural unsweetened cocoa powder: Cocoa gives these brownies their deep chocolate flavor. I recommend natural cocoa, not Dutch-processed, to maintain the correct leavening reaction.
- Unsalted butter: Butter brings rich flavor and moisture. Melted butter is key for mixing smoothly with the chocolate.
- Semi-sweet chocolate chips: Melted with the butter, this duo creates the ultimate fudgy base.
- Granulated sugar
- Vegetable oil: Oil keeps the brownies moist for days, even after cutting.
- Egg: Adds structure and binds everything together, especially important with the added moisture from zucchini.
- Vanilla extract
- Shredded zucchini: The moisture secret! Zucchini melts into the batter, leaving no taste—just the perfect chewy texture.
How to Make the Best Zucchini Brownies
You don’t need baking experience to be successful with my zucchini brownie recipe. I walk you through the simple process in detail! Follow my easy step-by-step guide:
For the Brownies
- Prep oven and pan. Preheat the oven to 350ºF. Lightly spray a 9×13-inch baking pan with nonstick spray or line it with parchment paper.
- Combine dry ingredients. In a medium bowl, whisk together the flour, salt, baking soda, and cocoa powder. Set aside.
- Melt butter and chocolate. In a saucepan over low heat, melt the butter and chocolate chips, stirring until smooth. Remove from heat.
- Mix in wet ingredients. Stir in the granulated sugar, vegetable oil, egg, and vanilla extract into the melted chocolate mixture. Mix until fully combined.
- Combine wet and dry ingredients. Add the dry ingredients to the wet mixture and stir until just combined.
- Add zucchini. Fold in the shredded zucchini until evenly distributed.
- Transfer batter. Pour the batter into the prepared pan and smooth out the top.
- Bake. Bake for 25–35 minutes, or until a toothpick inserted into the center comes out with a few moist crumbs.
- Cool. Let cool completely before adding the frosting or slicing and serving.
For the Frosting
- Combine ingredients. In a medium saucepan over low heat, heat the milk, cocoa powder, and butter until it just begins to boil. Remove it from the heat and sift in the powdered sugar, vanilla extract, and salt. Use a whisk or electric mixer to break up the powdered sugar clumps.
- Top brownies. Pour the frosting over the brownies. Allow the frosting to set completely before slicing and serving.
Baking Tips for Perfect Zucchini Brownies
- Measure accurately: Accurate measurements are everything, especially flour. Use a kitchen scale or the spoon-and-level method since too much flour is the fastest way to dry out brownies.
- Melt carefully: Melt the butter and chocolate slowly over low heat or in short microwave bursts to avoid scorching.
- Avoid overmixing: Once the dry ingredients are added, mix just until combined. Overmixing can lead to tough brownies.
- Use both butter and oil: The combo of butter and oil gives rich flavor and lasting moisture.
- Prep the zucchini correctly: Use the standard holes on a box grater or cheese shredder for the best texture. Do not squeeze or blot the zucchini. The natural moisture is what gives these brownies their signature fudgy texture. Removing the liquid will make the batter too dry and dense.
- Frosting tip: Let the brownies cool slightly before adding the boil-and-set frosting for that crackly finish.
- Upgrade your chocolate: For a gourmet twist, chopped chocolate bars can replace chips—just melt them with the butter.
- Go gluten-free: A 1:1 blend like King Arthur’s Measure for Measure works well.
- Cut clean slices: Wipe your knife clean between slices for perfect edges.
Storing Zucchini Brownies
Store completely cooled brownies in an airtight container in the refrigerator for up to 5 days. Store them in a single layer so they don’t stick, or place parchment paper between the layers.
Freezing Zucchini Brownies
Once the brownies have fully cooled, wrap them tightly in plastic wrap and place them in an airtight container or freezer-safe bag. Don’t forget to label them with the date.
When you’re ready to eat them, take the brownies out of the freezer and let them thaw in the refrigerator overnight or at room temperature on the counter. Once they’ve warmed to room temp, they’re ready to enjoy.
More Zucchini Desserts Recipes
Tap stars to rate!
Zucchini Brownie Recipe
Ingredients
- 2 cups (240g) all-purpose flour
- 1 tsp salt
- 1 tsp baking soda
- ½ cup (42g) natural unsweetened cocoa powder
- ½ cup (113g) unsalted butter
- ½ cup (3 oz) semi-sweet chocolate chips
- 1 ½ cups (297g) granulated sugar
- ½ cup (118ml) vegetable oil
- 1 large egg
- 1 tsp vanilla extract
- 2 cups (206g) shredded zucchini
Frosting
- ⅓ cup (79ml) milk
- 5 Tbsp natural unsweetened cocoa powder
- ½ cup (113g) unsalted butter
- 3 cups (341g) powdered sugar, sifted
- 2 tsp vanilla extract
- ½ tsp salt
Instructions
Brownies
- Preheat the oven to 350ºF. Lightly spray a 9×13-inch baking pan with nonstick spray or line it with parchment paper.
- In a medium bowl, whisk together the flour, salt, baking soda, and cocoa powder. Set aside.2 cups (240g) all-purpose flour, 1 tsp salt, 1 tsp baking soda, ½ cup (42g) natural unsweetened cocoa powder
- In a saucepan over low heat, melt the butter and chocolate chips, stirring until smooth. Remove from heat.½ cup (113g) unsalted butter, ½ cup (3 oz) semi-sweet chocolate chips
- Stir in the granulated sugar, vegetable oil, egg, and vanilla extract into the melted chocolate mixture. Mix until fully combined.1 ½ cups (297g) granulated sugar, ½ cup (118ml) vegetable oil, 1 large egg, 1 tsp vanilla extract
- Add the dry ingredients to the wet mixture and stir until just combined.
- Fold in the shredded zucchini until evenly distributed.2 cups (206g) shredded zucchini
- Pour the batter into the prepared pan and smooth out the top.
- Bake for 25–35 minutes, or until a toothpick inserted into the center comes out with a few moist crumbs.
- Let cool completely before adding the frosting or slicing and serving.
Frosting
- In a medium saucepan over low heat, heat the milk, cocoa powder, and butter until it just begins to boil. Remove it from the heat and sift in the powdered sugar, vanilla extract, and salt. Use a whisk or electric mixer to break up the powdered sugar clumps.⅓ cup (79ml) milk, 5 Tbsp natural unsweetened cocoa powder, ½ cup (113g) unsalted butter, 3 cups (341g) powdered sugar, 2 tsp vanilla extract, ½ tsp salt
- Pour the frosting over the brownies. Allow the frosting to set completely before slicing and serving.
