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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!
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
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
- 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!
This post was originally published on September 5, 2025
Way too watery and wet. 🙁
Hi Dana,
Very sorry to hear this. Next time, you could use a 9×13 baking dish to help with the baking. I hope this helps! xx
I’m curious, if I do not have a 9”x9” baking dish, could you use an 8”x8” or 9”x13”? Which would you suggest? I’m seeing that substituting either one may mean having to make adjustments to the amounts within the recipe, is this true?
Hey Alexandria,
Yes! You can use a 9×13 baking dish, they will be less thick, but more like a classic brownie. I hope you love this recipe, please let me know if you give it a try! xx
Yummy and rich! Definitely had to bake 20 minutes longer but maybe my zucchini was too wet? More of a rich cake than a brownie, but again, it may have been too watery from my zucchini.
Do you think this would freeze in individual portions okay? It’s just me and I won’t eat it all right away
Thanks so much, Madison! So glad you enjoyed this recipe, they are definitely thick brownies:) Yes, you could freeze these! Happy Monday! xx
Is there maybe a misprint? Why use powdered sugar in the base when the wonderful recipe you are basing this off of uses white sugar? These were wonderfully fudgy and chocolatey, but the next time I make them I will definitely go back to white sugar in the base. I appreciate your recipes, you have such a good ability to pull flavors together. Thank you!
Thanks so much, Deborah!! No, there is no misprint:) I just enjoyed the powdered sugar this time around. Thanks again for making the recipe! xT
These are the best zucchini brownies I’ve made! A real rich fudge flavor and texture in the middle and the frosting is delicious! I made the recipe as is and it turned out perfect.
Hey Allison,
Happy Monday! Love to hear these brownies were a hit, thanks a bunch for making them!
Enjoy your day! x
Just confirming that we shouldn’t expect a toothpick to come out clean to know it’s done? Just that it has dry edges and set center??
Hi Shauna,
Correct:) I hope you love these brownies! Have a great week! xT
Similar to the commenter just before me, I don’t know what the issue was with the original raters, because this recipe is perfect! I made sure to squeeze the water out of my shredded zucchini first and followed the recipe exactly, baking for 35 minutes. I also have a daughter with a dairy allergy so I substituted the milk and butter for vegan versions and made sure my chocolate chips were also dairy-free. They were moist and rich. The entire recipe is a winner and the perfect way to use up the overflowing bounty of zucchini!
Hey Kelsey,
Yay!! Thanks a bunch for making these brownies:) I’m so glad to hear they were enjoyed. Thanks for sharing your notes and what worked well for you! Have a great week! xT
I’m not sure what the other commenters did that varied their experience, but the brownies I made were amazing! Perfect fudgy texture and rich chocolate taste. Although I was unsure of the frosting when I was making it, when it set, it was the perfect frosting consistency. My family gobbled them up! Very rich and delicious. I will definitely be making these again.
Hey Erin, Thanks a bunch for trying these brownies! I’m so glad to hear that they turned out well for you:) Have a wonderful week ahead! xT
These were amazing! It was a great way to use up some zucchini. They were chocolatey and delicious.
Thanks so much, Jenny! Love to hear this recipe was enjoyed! Happy Monday!
These ended up more like a cake than brownie – it seems really similar to the latest “hostess cake” recipe. It was ok but not what I was expecting, especially when I was looking for a brownie consistency.
Hey Maddie! Yes these are thick brownies for sure! You can bake them in a 9×13 inch baking dish for a thinner brownie if that is what you prefer!
I’m sorry these didn’t fit perfectly for you! Maybe this adjustment will help.
I hope you enjoy! Have a great week!
Can I use almond flour instead of all purpose flour?
Hey Amy,
So sorry, I have not tested this recipe with almond flour, I’m not sure it would be the best option here but you could certainly give it a try! I think gluten free flour blend would work better. Have a great Sunday! xx
These did not work for me at all, too much moisture even with longer time in the oven.
Hi Janet, Thanks for trying these brownies. Was it just that they did not bake up well? Did they taste okay? Please let me know how I can help! x
I always squeeze my zucchini in paper towels after I shred it when I use it for baking. Makes a big difference. I made these today and the consistency was perfect!
These don’t taste like brownies at all. It is more like a cake recipe. They are not thick or fudge, so it’s surprising to me that is what they are called. I won’t make these again. Maybe the recipe could be adapted to be a cake, but I’m not sure. We ended up putting ours into a mixer to make cakeballs.
Hi Michael, Sorry to hear this. I appreciate you trying the recipe and your feedback. Have a nice Sunday!
Can you substitute Splenda for the powdered sugar
Hi Angela, So sorry, I would not recommend that. Please let me know if I can help in any other way! xx
Could you swap squash for the zucchini?
Hi Paige,
Sure, that would be just fine for you to do. I hope you love this recipe! xx
When I try and print this recipe the ounces needed does one show., I only get a bag of chops not 12 oz. Am I doing something wrong?
Hi Gale, Thanks for pointing this out, I’m not sure why it does not show the ounces. You will want to use a 10 oz bag of mini chocolate chips. I hope you love this recipe! xx