These brownies are everything you want in a treat: thick, fudgy, and unapologetically chocolatey. You’d never guess there’s a full dose of zucchini inside, adding moisture without a veggie taste. The frosting is glossy, rich, and sets into a smooth layer that takes each bite over the top.
If you’re looking for a dessert that checks every box—easy, impressive, and crowd-pleasing—this is the one. Perfect for using up garden zucchini or making any weeknight feel special.
What Makes This Special
These brownies balance deep chocolate flavor with a velvety, almost truffle-like texture. The zucchini melts into the batter, giving natural moisture so you don’t need a ton of butter or oil.
There’s no wringing or draining required—just grate and stir. The stovetop frosting adds a classic, nostalgic touch with a glossy finish and a hint of salt to keep the sweetness in check.
Best of all, this recipe is forgiving and flexible. You can bake it in one bowl, swap in your favorite add-ins, or make it dairy-free with simple tweaks.
It’s a great bake for beginners and a reliable go-to for seasoned home bakers.
What You’ll Need
- 1 1/2 cups finely grated zucchini (no need to peel or squeeze)
- 1 cup granulated sugar
- 1/2 cup brown sugar (light or dark)
- 1/2 cup neutral oil (canola, avocado, or light olive oil)
- 2 large eggs, room temperature
- 2 teaspoons vanilla extract
- 1 cup all-purpose flour
- 1/2 cup unsweetened cocoa powder (Dutch-process or natural)
- 1 teaspoon baking powder
- 1/2 teaspoon baking soda
- 1/2 teaspoon fine sea salt
- 3/4 cup chocolate chips (optional but recommended)
For the frosting:
- 4 tablespoons unsalted butter
- 1/4 cup milk (dairy or unsweetened non-dairy)
- 1/4 cup unsweetened cocoa powder
- 2 cups powdered sugar, sifted
- 1 teaspoon vanilla extract
- Pinch of salt
Equipment: 8×8-inch baking pan, parchment paper, mixing bowl, whisk, spatula, box grater, small saucepan.
Step-by-Step Instructions
- Prep the pan and oven. Heat the oven to 350°F (175°C). Line an 8×8-inch pan with parchment, leaving overhang for easy lifting. Lightly grease the sides.
- Grate the zucchini. Use the fine side of a box grater.
Pack lightly into a measuring cup. Don’t squeeze out moisture; you want the hydration for fudginess.
- Combine wet ingredients. In a large bowl, whisk sugar, brown sugar, and oil until glossy. Add eggs and vanilla and whisk until smooth and slightly thick, about 30 seconds.
- Whisk dry ingredients. In a separate bowl, whisk flour, cocoa powder, baking powder, baking soda, and salt to break up lumps.
- Make the batter. Add dry ingredients to the wet and fold gently until just combined.
The batter will look thick. Fold in the zucchini and chocolate chips; the batter will loosen as the zucchini releases moisture.
- Fill the pan. Spread the batter evenly in the prepared pan. Smooth the top with a spatula.
- Bake. Bake for 28–34 minutes, until the center is set and a toothpick comes out with a few moist crumbs (not wet batter).
Err on the side of slightly underbaked for fudgy texture.
- Cool before frosting. Let the brownies cool in the pan on a rack for 20–30 minutes. They should be warm, not hot, when frosting goes on.
- Make the frosting. In a small saucepan, melt butter over low heat. Whisk in milk and cocoa until smooth and just steaming.
Remove from heat, whisk in powdered sugar, vanilla, and a pinch of salt until glossy and spreadable. If too thick, add 1–2 teaspoons milk; if too thin, add a bit more powdered sugar.
- Frost. Pour frosting over the warm brownies and spread to the edges. The warmth helps it set into a shiny layer.
- Set and slice. Let the frosting firm up for at least 30 minutes.
Lift out using the parchment and slice with a sharp knife, wiping the blade between cuts for clean edges.
How to Store
- Room temperature: Keep covered at room temp for up to 2 days. The frosting will stay soft but set.
- Refrigerator: Store in an airtight container for 4–5 days. Chilled brownies are denser and extra fudgy.
- Freezer: Freeze slices on a sheet until firm, then wrap individually.
Store up to 2 months. Thaw at room temp for 30–45 minutes.
Health Benefits
While these are definitely a treat, the zucchini brings a few perks. It adds fiber, potassium, and hydration to the batter, which helps keep the brownies moist without relying solely on fat.
Using cocoa powder provides flavanols, which are plant compounds with antioxidant properties.
You can also make small tweaks for a more balanced dessert. Swap half the flour for white whole wheat flour, use less sugar if your chocolate chips are sweet, or choose a neutral oil rich in monounsaturated fat like avocado oil. These adjustments keep the texture indulgent while nudging the nutrition in a better direction.
Pitfalls to Watch Out For
- Overbaking: The fastest way to dry brownies.
Pull them when the center is set and the toothpick shows moist crumbs.
- Draining the zucchini: Don’t squeeze out the moisture. You’ll lose the fudgy texture.
- Skipping the sift: Lumpy powdered sugar leads to grainy frosting. Sift for a silky finish.
- Wrong pan size: A larger pan makes thin, overbaked brownies; a smaller one may underbake.
Stick to 8×8 or adjust time carefully.
- Frosting too hot: If the brownies are piping hot, the frosting can separate. Let them cool until warm before spreading.
Alternatives
- Dairy-free: Use plant-based butter and non-dairy milk in the frosting. The brownie batter already uses oil, so it’s an easy swap.
- Gluten-free: Use a 1:1 gluten-free all-purpose blend with xanthan gum.
Bake time may vary by a few minutes.
- No frosting: Dust with powdered sugar or drizzle melted chocolate. Or swirl in 2–3 tablespoons warm hazelnut spread before baking.
- Extra chocolatey: Add 2 tablespoons espresso or strong coffee to the batter to deepen the cocoa flavor.
- Nutty crunch: Fold in 1/2 cup chopped walnuts or pecans with the chocolate chips.
- Lower sugar: Reduce granulated sugar by 2–3 tablespoons and use dark chocolate chips. Texture remains moist thanks to the zucchini.
FAQ
Do I need to peel the zucchini?
No.
The peel is thin and disappears during baking. It adds color flecks and a bit of nutrition without affecting taste.
Will I taste the zucchini?
Not at all. It acts like moisture, similar to applesauce or mashed banana, but without a fruity flavor.
All you taste is chocolate.
Can I make these ahead?
Yes. Bake and frost up to a day in advance. Store covered at room temperature, or refrigerate for a firmer, fudgier bite.
How do I know when they’re done?
Look for set edges and a center that doesn’t jiggle.
A toothpick should come out with a few moist crumbs. If it’s completely dry, they’re likely overbaked.
Can I double the recipe?
Yes. Use a 9×13-inch pan and bake for 32–40 minutes, checking near the 30-minute mark.
Frosting can be doubled as written.
What kind of cocoa powder works best?
Both Dutch-process and natural work. Dutch will give a deeper, smoother chocolate flavor. If using Dutch, keep the leavening as written—this recipe balances both types.
Can I use coconut oil?
Yes.
Melt it and let it cool slightly before mixing. Expect a faint coconut aroma unless you use refined coconut oil.
Why is my frosting grainy?
Powdered sugar likely wasn’t sifted, or the cocoa mixture was too hot. Sift the sugar and whisk off heat until smooth; a splash more milk can help loosen it.
Do I have to add chocolate chips?
No, but they add pockets of gooey chocolate.
If skipping, consider increasing cocoa by a tablespoon for extra richness.
What if my batter looks too thick?
Once you stir in the zucchini, it will loosen as the moisture releases. If it still seems dry, let it rest 2–3 minutes, then fold again.
Wrapping Up
These fudgy zucchini brownies deliver big chocolate flavor with a beautifully soft crumb and a shiny, nostalgic frosting. They’re simple to make, hard to mess up, and easy to customize.
Whether you’re baking for a potluck or just treating yourself, this is a keeper recipe you’ll come back to again and again. Grab a square, pour a glass of milk or coffee, and enjoy every rich, decadent bite.