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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!

Thick and Fudgy Zucchini Brownies | halfbakedharvest.com

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.

Thick and Fudgy Zucchini Brownies | halfbakedharvest.com

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!

Thick and Fudgy Zucchini Brownies | halfbakedharvest.com

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.

Thick and Fudgy Zucchini Brownies | halfbakedharvest.com

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.

Thick and Fudgy Zucchini Brownies | halfbakedharvest.com

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.

Thick and Fudgy Zucchini Brownies | halfbakedharvest.com

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.

Thick and Fudgy Zucchini Brownies | halfbakedharvest.com

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.

Thick and Fudgy Zucchini Brownies | halfbakedharvest.com

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.

Thick and Fudgy Zucchini Brownies | halfbakedharvest.com

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

Prep Time 20 minutes
Cook Time 40 minutes
Total Time 1 hour
Servings: 16 brownies
Calories Per Serving: 204 kcal

Nutritional information is only an estimate. The accuracy of the nutritional information for any recipe on this site is not guaranteed.

Ingredients

Frosting

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!
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This post was originally published on September 5, 2025
3.49 from 27 votes

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Comments

  1. The grayed zuccini is very wet. Should I lay it dry and remove some of the moisture before combining it with the ingredients?

    1. Hi Gracie,
      No, you do not need to do that for this recipe:) Please let me know if you have any other questions!

    1. Hi Patricia,
      Happy Friday! I really appreciate you making this recipe and reporting back. Thrilled it turned out well!

  2. 5 stars
    I’m not sure how these are rated 3.3 stars. They are delicious. I have made them multiple times. My kids love them. Perfectly sweet and fudgy.

  3. 5 stars
    If you’re not giving this 5 stars, you’re doing it wrong. This is the best homemade brownies I’ve ever made. You would never guess there is zucchini in it. Thank for you sharing this recipe! Now my garden zucchini won’t go to waste.

    1. Hey Megan,
      Thanks for the thoughtful feedback after trying this recipe, I’m happy to hear it was a win! Have the best weekend:)

  4. 2 stars
    I made these exactly as the recipe states, baked for 30 minutes. Mine were not really fudgy or brownie like at all! They turned out like a cake texture. Disappointed, my search for a really fudgy brownie continues!

  5. 5 stars
    Fudgy & delicious. I did skip the second helping of chocolate chips, as I didn’t desire them to be that rich. Only had dark cocoa at the time, turned out great. So much garden zucchini to use up!

    1. Hey Rosa, I really appreciate you making this recipe and reporting back. Thrilled it turned out well! Have the best weekend!

    1. Hi Mackenna, Thanks so much for trying these brownies and your feedback! So sorry you didn’t love the texture. Have a great weekend!

    1. Hi Sam,
      Thanks for trying these brownies, sorry to hear they were not enjoyed.

      Is there anything that I can help with? Please let me know!