Zucchini Brownies with Peanut Butter Frosting

By: Melissa Erdelac · On: August 21, 2018 · Updated: May 4, 2021

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The best Zucchini Brownies recipe has easy-to-make fudgy brownies with fluffy peanut butter frosting, all covered in a chocolate glaze.

Whether you want to sneak in some healthy vegetables or just want to enjoy a moist and fudgy brownie, this gluten free or traditional recipe is for you!

one zucchini brownie with peanut frosting on top of two other ones and chocolate chips around

Using zucchini is baked goods, such as brownies or gluten free zucchini bread, adds moistness without the need for extra fat, such as butter or oil. It also builds structure and texture, reducing the amount of flour needed.

Zucchini also has many health benefits, such as in savory recipes like, zucchini fries, grilled zucchini, sauteed, or roasted. Plus, its neutral flavor means complimenting a variety of ingredients and dishes!

Of all the ways to use zucchini, though, throwing it in frosted brownies has to be my favorite because of the ultra fudgy moistness it adds. Zucchini brownies with frosting has become my number one requested dessert. Bake them for yourself and see what I mean!

Why you’re going to love this recipe!

No grating zucchini necessary! If you have a food processor, just throw the ingredients in and the brownie batter mixes, while the zucchini pulverizes. (No worries if you don’t have a food processor, though, I included traditional instructions too. 🤗)
Fluffy peanut butter frosting slathered on a decadent brownie with chocolate glaze – Count. Me. In. You might have clued in to my peanut butter / chocolate obsession with Buckeye Turtle Brownies, Peanut Butter Sandwich Cookies, Chunky Monkey Cake, or Peanut Butter Quick Bread. Whaddayathink?
Gluten free adaptation – Need gluten free zucchini brownies? No problem! These brownies have been tested with traditional and gluten free flour, both with amazing results. Check out more gluten free zucchini recipes!

How to Make Zucchini Brownies

(Note: This is a step-by-step tutorial with pictures. For more specific instructions, along with ingredient amounts, see the recipe card at the bottom of the post.)

Place the zucchini, eggs, and melted butter in a food processor. Mix until everything is smooth and pulverized. If you do not have a food processor, use 3 cups shredded zucchini.
Add the sugar, cocoa powder, regular or gluten free flour, baking powder, and salt. Process until just combined.
Add the chocolate chips and pulse a few times. This makes the brownies extra fudgy. Pour batter into a 9X13 pan and bake for 30-35 minutes.
After brownies are cool, beat together peanut butter frosting ingredients – creamy peanut butter, butter, powdered sugar, and milk. Spread on evenly.
Melt together the chocolate chips with butter in the microwave. Stir until smooth and then spread the chocolate frosting over the peanut butter layer. Chill for 15 minutes before cutting into squares.

close up over peanut butter frosting on top of brownies

frequently asked questions

Can yellow squash be substituted?

Yes, any summer squash may be substituted. Smaller ones are preferred because tender and don’t have as many seeds.

If you have a larger zucchini or squash with lots of seeds, simply halve and scoop the seeds out of the middle with a spoon.

Can these brownies be made gluten free?

Yes. To make gluten free zucchini brownies, simply substitute an all purpose gluten free flour in the recipe. My favorite to use is Cup4Cup because no one can detect any difference in taste. Find out more about how the flours compare in the gluten free flour guide.

Is there a way to make this recipe healthier?

Still want a fudgy, chocolate brownie without all the extra calories? Here are some suggested substitutions:
-Use an unrefined sugar, such as coconut sugar.
-Switch out whole wheat flour for regular all-purpose
-Instead of butter, use an equal amount of coconut oil, which will also make the brownies dairy-free.
-Skip the frosting. Dust brownies with powdered sugar instead or leave plain.

Can I make these dairy-free?

Yes. Swap out the melted butter with vegan butter sticks or melted coconut oil. Use dairy-free chocolate chips and plant-based butter for the peanut butter frosting.

best Tips and Tricks

If you don’t have a food processor use a grater and measure out 3 cups of shredded zucchini instead.
This recipe can easily be halved and baked in a 8″ or 9″ square pan. Bake for 30 minutes.
Using Dutch processed cocoa powder makes for a deeper, darker chocolate taste, but natural unsweetened baking cocoa may be substituted.
The peanut butter frosting may be left off. Simply top with the chocolate glaze or combine 6 tablespoons cocoa powder, 4 tablespoons melted butter, 2 cups powdered sugar, and 1/4 cup milk in a medium bowl. Spread on slightly warm brownies.
Turn these into a festive treat! Forgo the peanut butter topping, use cream cheese frosting, and decorate as 4th of July brownies.

top of a brownie with shiny chocolate frosting

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