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Thick and Fudgy Zucchini Brownies. Back to the classics with these extra-delicious frosted brownies made with grated zucchini and topped with the most indulgent fudge frosting. Think rich salted butter, melty chocolate chips, a touch of cocoa, and just enough zucchini to keep them extra moist and thick. Once baked, they’re finished with a creamy, old-fashioned chocolate fudge frosting. Simple, classic, and so good!
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It’s been a minute since I last baked a batch of brownies, but they’ve always been a family favorite. The other week I had a few zucchini sitting in the fridge, and I knew I needed to put them to good use. This time of year it always seems like there’s either an abundance of zucchini or tomatoes — and I hate to see food go to waste. Brownies felt like the perfect answer.
I was excited to bake these up, especially since brownies are my little sister’s favorite treat. Even with the addition of zucchini, I knew she’d be into them (and she was!). I used one of my tried-and-true base brownie recipes, adding just a hint of lightly toasted butter, which I swear makes all the difference in flavor.
And of course…the frosting. I wanted these to be really special, so I went with a thick layer of homemade fudge frosting — the kind that feels nostalgic, like something your grandma might have spread over her brownies. Classic, rich, and perfectly fudgy. Nothing fancy, just delicious.
These are the details
Ingredients
- Salted butter
- 1 bag of mini chocolate chips
- Pure vanilla extract
- Eggs – make sure they are at room temperature and not at all chilled
- All-purpose flour
- Cocoa powder
- Baking powder
- Sea salt
- Chocolate chips – I love to use dark chocolate chips
Ingredients – for the Frosting
- melted butter
- powdered sugar
- cocoa powder
- vanilla extract
- warm milk
Special Tools
You’ll need a skillet, a couple of mixing bowls, and a square brownie pan.
Steps
Step 1: Grate the zucchini
Grate the zucchini on a box grater using the smaller holes. This gives you fine zucchini pieces that melt right into the batter, keeping the brownies soft and fudgy without big chunks. You’ll hardly even notice it’s there!
Step 2: Brown the butter
Add the cold, salted butter to a skillet — I love using cast-iron. Let the butter sizzle and brown over medium heat, about 5 minutes, until it smells nutty and golden.
Step 3: Add the chocolate
Remove the pan from the heat and stir in the chocolate until it’s melted and smooth. Mix in the vanilla.
Step 4: Whisk the eggs
In a separate bowl, whisk the eggs really well. This step is key — whisking creates air that gives you that shiny, crinkly brownie top. It might seem unnecessary, but trust me, it makes all the difference.
Step 5: Mix in the zucchini and finish the batter
Whisk the eggs into the chocolate mixture, then stir in the grated zucchini. Add the powdered sugar, flour, cocoa powder, baking powder, and salt. Mix until the batter is smooth and glossy. Fold in a big handful of dark chocolate chips.
Step 6: Bake
Spread the batter into a 9×9-inch square pan lined with parchment. Bake at 350° F for about 30 minutes, until set in the center.
Step 7: Make the frosting
Stir together melted butter, powdered sugar, cocoa powder, and warm milk — the warm milk brings it all together into a glossy frosting. It will look drizzly at first, but it sets perfectly over the brownies.
Frost the cooled brownies, then let the frosting set for 1–2 hours before slicing.
Looking for other sweet recipes? Here are a few ideas:
Baked Apple Cider Doughnuts with Cinnamon Maple Glaze
Brown Butter Apple Blondies with Cinnamon Maple Glaze
Spiced Pecan Apple Cider Doughnut Cake
Mulled Spiced Apple Cider Doughnuts
Double the Streusel Apple Butter Bars
Homemade Slow Cooker Maple Apple Butter
Lastly, if you make these Thick and Fudgy Zucchini Brownies, be sure to leave a comment and/or give this recipe a rating! Above all, I love to hear from you guys and always do my best to respond to each and every comment. And of course, if you do make this recipe, don’t forget to tag me on Instagram! Looking through the photos of recipes you all have made is my favorite!
Thick and Fudgy Zucchini Brownies
Ingredients
- 1 stick (1/2 cup) salted butter
- 1 bag (10) ounce) mini chocolate chips
- 1 1/2 cups powdered sugar
- 1 tablespoon vanilla extract
- 4 large eggs, at room temperature
- 1 cup grated zucchini
- 1/2 cup all-purpose flour
- 1/2 cup unsweetened cocoa powder
- 3/4 teaspoon baking powder
- 1/2 teaspoon sea salt
- 1/2 cup semi sweet or dark chocolate chips
Frosting
- 4 tablespoons salted butter, melted
- 2-3 cups powdered sugar
- 1/4 cup cocoa powder
- 1 teaspoon vanilla extract
- 2 tablespoons warmed milk
Instructions
- 1. Preheat the oven to 350° F. Line a 9×9 inch square pan with parchment paper.2. Add the butter to a pot set over medium heat. Allow the butter to brown lightly until it smells toasted, 2-3 minutes. Remove from the heat. Mix in the mini chocolate chips until all are melted. Stir in the vanilla. 3. In a bowl, whisk the eggs for 1 minute until bubbly on top. Add the melted chocolate and powdered sugar, whisking until smooth, 1-2 minutes. Mix in the grated zucchini. Add the flour, cocoa powder, baking powder, and salt. Stir until just combined. Stir in the chocolate chips.4. Spread the batter into the prepared pan. Bake for 30-35 minutes or until the brownies are just set. They will be thick. 5. To make the frosting. Whisk the butter, 2 cups powdered sugar, cocoa powder, vanilla, and warm milk in a bowl, adding additional warm milk until the frosting becomes thicker, but still drizzly. Taste, adding more sugar if needed. Spread the frosting over the brownies. Let set for 1-ish hour…or slice, snack, and enjoy!
Nutrition
Nutritional information is only an estimate. The accuracy of the nutritional information for any recipe on this site is not guaranteed.
Did you make this recipe? Please rate & comment below.
Ok this idea is out there but thoughts on swapping the zucchini for sweet potato? Or I’d love to see you develop a sweet potato brownie recipe. The internet is chock full of healthy sweet potato brownie recipes but sorely lacking in really indulgent ones and I am overflowing in CSA sweet potatoes this fall.
Hi Emily,
Love this idea! I’ve never tried using sweet potato here, but you could definitely test it out! I hope you love these brownies.
Pretty yummy! The final texture feels more like a slice of cake than brownie. Curious to know why powdered sugar is called for rather than granulated.
Hey Rachel,
Awesome! Thanks so much for making this recipe and your comment, so glad it was enjoyed!
The powdered sugar gives a smoother texture in the brownies.
These were perfect if you love moist brownies it was almost like lava cake sooo decadent and good esp with the frosting but I served it to my kids without any frosting bc it was already sweet enough
Hey Sharon,
Perfect! Thanks so much for making this recipe, I am so glad it was a hit! Have a great Labor Day weekend!
Did anyone else have to bake these for way longer than it said?
Hey Alex,
So sorry to hear this!! What kind of baking dish did you use? That might have been the issue. I hope they tasted okay!