Zucchini Bars with Brown Butter Frosting

These Zucchini Bars with Brown Butter Frosting Are So Good, You'll Forget They're Made with Veggies

I remember the first time I baked zucchini into a dessert. I was skeptical. Could vegetables really belong in something sweet and indulgent? But that all changed the moment I took a bite of these soft, spiced zucchini bars with rich, nutty brown butter frosting. Suddenly, zucchini became my secret weapon for incredibly moist sheet cake-style treats that my whole family couldn’t stop devouring.

If you're like me and looking for a way to sneak some healthy ingredients into your desserts—without sacrificing flavor or fun—this is your golden ticket. These zucchini bars are perfect for summer baking, especially when gardens and farmers' markets are overflowing with fresh, green squash. Whether you’re making them for your family, a casual get-together, or just because you deserve something delicious, these dessert squares are guaranteed to win hearts.

Let’s dive into why these zucchini bars with brown butter frosting deserve a place in your summer baking rotation—and your recipe box.

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Why You’ll Love These Zucchini Bars

These bars check every box for a modern, busy woman who still wants to wow with her baking skills:

They’re easy to make (one bowl, one pan, no fancy equipment).

The grated zucchini adds moisture without tasting like veggies.

The brown butter frosting gives these dessert squares a gourmet bakery feel.

They’re kid-approved and subtly healthy, making them perfect family treats.

It’s like eating a moist sheet cake, only cut into hand-held squares.

Trust me, these are the kind of treats your girlfriends will ask you about after the first bite—and the kind your kids will beg for after school.

Ingredients You’ll Need

Here’s exactly what you’ll need for the bars and frosting. This recipe makes about 20–24 dessert squares, depending on how you slice them.

For the Zucchini Bars:

2 cups grated zucchini (about 2 medium zucchinis)

2 cups all-purpose flour

1 ½ cups granulated sugar

2 large eggs

½ cup vegetable oil

¼ cup unsalted butter, melted

2 teaspoons vanilla extract

1 teaspoon baking soda

½ teaspoon baking powder

½ teaspoon salt

2 teaspoons ground cinnamon

For the Brown Butter Frosting:

½ cup (1 stick) unsalted butter

2 cups powdered sugar, sifted

1 teaspoon vanilla extract

2–3 tablespoons milk or heavy cream

Step-by-Step Instructions

1. Prep Your Zucchini

First things first: grate your zucchini. I recommend using the medium holes on a box grater for a nice, even texture. You’ll want to lightly squeeze out any excess liquid using a clean kitchen towel or paper towel. You don’t need to wring it dry—just enough so it’s not dripping wet. This will help the bars hold their shape while staying perfectly moist.

Tip: Don’t peel the zucchini! The skin is tender and adds great color and nutrients.

2. Make the Batter

In a large mixing bowl, whisk together:

2 eggs

1 ½ cups sugar

½ cup oil

¼ cup melted butter

2 tsp vanilla extract

Once well combined, stir in the grated zucchini.

In a separate bowl, mix the dry ingredients:

2 cups flour

1 tsp baking soda

½ tsp baking powder

½ tsp salt

2 tsp cinnamon

Gradually stir the dry ingredients into the wet mixture. Mix until just combined—don’t overmix.

3. Bake

Pour the batter into a greased 9x13-inch baking pan and smooth it out evenly.

Bake at 350°F (175°C) for 30–35 minutes, or until a toothpick comes out clean. The top should be golden and the edges slightly pulled away from the pan.

Let it cool completely before frosting.

Let’s Talk About That Frosting…

Brown butter is a game-changer. It adds a rich, nutty flavor that pairs beautifully with the spiced zucchini base. You’ll never go back to regular frosting again.

Here’s how to make it:

1. In a small saucepan, melt ½ cup butter over medium heat.

2. Continue cooking until it foams and turns a deep golden brown, with a nutty aroma (about 5–7 minutes).

3. Remove from heat and let it cool for 5 minutes.

4. In a bowl, combine browned butter with:

2 cups powdered sugar (sifted)

1 tsp vanilla

2–3 tbsp milk or cream

Beat until smooth and spreadable. Pour over the cooled zucchini bars and smooth it with an offset spatula.

Let it set for about 20 minutes before cutting into dessert squares.

Amazon Product Recommendations for This Recipe

To make this recipe easier and even more enjoyable, here are three of my go-to kitchen tools I use every time I bake these bars:

1. OXO Good Grips Box Grater

If you’re still struggling with an old, dull grater, it’s time for an upgrade. This one has a non-slip base, sharp stainless steel blades, and a convenient storage container for catching grated zucchini with less mess.

Grab it on Amazon – Make grating smoother and safer for your summer baking sessions.

2. USA Pan Bakeware 9x13 Nonstick Pan

This heavy-duty, commercial-grade nonstick baking pan is a total game changer. It bakes evenly, doesn’t warp, and the bars come out beautifully every time—no sticking, no mess.

Check it out here – A solid investment for any home baker who loves easy clean-up and perfect results.

3. Cuisinart 1-Quart Stainless Steel Saucepan

Perfect for browning butter without scorching it. The pour spout makes it easy to transfer the butter to your mixing bowl. Small enough to handle easily, but big enough for daily cooking and baking.

See it on Amazon – Upgrade your sauce game and get flawless brown butter every time.

Why These Bars Are Perfect for Summer

Summer is zucchini season! Whether you grow your own or pick it up at the local market, there’s no better time to turn it into dessert. These bars are:

Travel-friendly for BBQs, pool parties, or picnics.

Lightly spiced and perfectly moist—ideal for warmer weather.

A great way to use up garden zucchini without making another stir-fry.

Plus, because they’re cut into dessert squares, they’re easier to serve at outdoor gatherings compared to a full sheet cake.

Healthier Than You’d Expect

Sure, these bars have frosting—but there are some sneaky health perks too!

Zucchini is rich in fiber, potassium, and vitamin C.

The recipe uses only ½ cup oil, keeping it lighter than many cakes.

You can swap half the flour for whole wheat flour and reduce sugar by ¼ cup without sacrificing taste.

It’s a treat you’ll feel good about serving your family, especially if you’re trying to cut back on store-bought snacks for your kids.

Storage & Make-Ahead Tips

These bars are ideal for prepping ahead of time:

Store covered at room temperature for up to 2 days, or in the fridge for up to 5 days.

They also freeze well (just skip the frosting until you're ready to serve).

You can bake the bars the night before and frost them the next day for events.

Final Thoughts: From Skeptic to Superfan

Writing this blog post brought back so many memories of my first time baking with zucchini. I was a new mom, short on time but wanting to make something fun and nutritious. I never expected my toddlers to fall in love with something green in a dessert, but they did—and so did I.

Now, these zucchini bars with brown butter frosting are a go-to in my house. They’re easy, moist, healthy-ish, and they truly taste like something from your favorite bakery. Whether you’re looking for a fun way to use up summer produce, a crowd-pleasing potluck dessert, or a new family favorite—this recipe is it.

You might just find yourself making a double batch next time.