Easy Double Chocolate Zucchini Bars

I didn’t know what to do with zucchini until my neighbor dropped off three grocery bags of them on my porch one summer. I’d never grown it myself, and honestly, I’d only eaten it in stir-fry maybe twice before that.

That’s when I discovered you can hide zucchini in just about anything chocolate, and nobody notices. These double chocolate zucchini bars became my answer to the great zucchini overflow. The shredded zucchini basically disappears into the batter—all you taste is rich, fudgy chocolate. My kids ate four batches before they even knew there was a vegetable involved.

What Kind of Zucchini Should I Use?

For these chocolate bars, you’ll want to use a medium-sized zucchini that’s about 6-8 inches long. Smaller zucchinis tend to be more tender and have fewer seeds, which means less moisture and a better texture in your bars. If you only have a larger zucchini on hand, that’s fine too – just make sure to squeeze out any excess moisture after grating it. There’s no need to peel the zucchini before grating, as the skin will blend right into the batter and you won’t even notice it’s there. Just give it a good wash and you’re ready to go.

Options for Substitutions

This recipe is pretty forgiving when it comes to swaps, so here are some options if you need them:

• Semi-sweet chocolate bar and chips: You can use dark chocolate or milk chocolate instead, depending on your preference. Just keep in mind that milk chocolate will make the bars sweeter, while dark chocolate will give them a more intense cocoa flavor.
• Salted butter: Unsalted butter works fine – just add a pinch of salt (about 1/4 teaspoon) to the batter. You can also use coconut oil for a dairy-free option, though the flavor will be slightly different.
• All-purpose flour: For a gluten-free version, try a 1:1 gluten-free baking flour blend. The texture might be slightly different, but it’ll still work well.
• Granulated sugar: You can swap this with coconut sugar for a less refined option, though your bars will have a deeper, caramel-like flavor and darker color.
• Zucchini: Yellow squash works as a direct replacement and you won’t notice much difference. Make sure to squeeze out excess moisture from the grated zucchini or squash with a clean kitchen towel before adding it to the batter.

Watch Out for These Mistakes While Baking

The biggest mistake when baking with zucchini is forgetting to squeeze out the excess moisture – after grating your zucchini, wrap it in a clean kitchen towel or paper towels and give it a good squeeze to remove extra water that could make your bars soggy.

Overbaking is another common issue that turns fudgy brownies into dry, cakey bars, so pull them from the oven when a toothpick inserted in the center comes out with a few moist crumbs, not completely clean.

To get perfectly even bars, make sure your chocolate and butter mixture cools for a few minutes before adding the eggs – if it’s too hot, you’ll end up with scrambled eggs in your batter.

Finally, resist the urge to cut into these bars right away, as letting them cool completely in the pan helps them set up properly and makes slicing much cleaner and easier.

What to Serve With Double Chocolate Zucchini Bars?

These bars are rich and fudgy, so they’re perfect on their own with a cold glass of milk or a hot cup of coffee. If you want to make them feel more like a dessert, add a scoop of vanilla ice cream on top while they’re still slightly warm – the contrast between the cold ice cream and warm chocolate is really good. They also pair nicely with fresh berries like raspberries or strawberries, which add a little tartness that balances out the sweetness. For a casual get-together, serve them alongside other dessert bars or brownies to create a fun dessert spread that everyone can enjoy.

Storage Instructions

Store: Keep these chocolate zucchini bars in an airtight container at room temperature for up to 3 days, or in the fridge for up to a week. They actually taste even better the next day once the flavors have had time to settle in together.

Freeze: These bars are great for freezing! Cut them into individual portions, wrap each one in plastic wrap, and store in a freezer-safe container for up to 3 months. It’s nice to have a stash ready whenever a chocolate craving hits.

Thaw: Just let the bars sit at room temperature for about 30 minutes to thaw, or if you’re impatient like me, pop one in the microwave for about 15-20 seconds. They’re also pretty good eaten straight from the freezer if you like a fudgier texture.

Estimated Nutrition

Estimated nutrition for the whole recipe (without optional ingredients):

• Calories: 2400-2600
• Protein: 28-32 g
• Fat: 130-145 g
• Carbohydrates: 320-340 g

Ingredients

For the batter:

• 4.5 oz chocolate bar (I use Ghirardelli 60% Cacao semi-sweet baking bars)
• 1/2 cup butter (I like Kerrygold unsalted butter for this)
• 1 cup sugar
• 3 eggs (room temperature, about 70°F)
• 1 1/2 tsp vanilla
• 2/3 cup flour (I always use King Arthur all-purpose flour)
• 1/4 cup cocoa
• 1 cup chocolate chips
• 1 cup zucchini (finely shredded and squeezed dry of excess moisture)
• 1/2 tsp salt
• 1/2 tsp instant espresso powder

For the topping:

• 2 tbsp chocolate chips
• 1 pinch flaky sea salt

Step 1: Prepare Pan and Preheat Oven

Heat your oven to 320°F and grease a 9×13 inch baking dish (or 8×8 inch for thicker bars).

I recommend using parchment paper for easy removal after baking.

Step 2: Melt Chocolate and Butter

• 4.5 oz chocolate bar
• 1/2 cup butter

Chop the 4.5 oz chocolate bar into small pieces and combine with butter in a microwave-safe bowl.

Microwave in 30-second intervals, stirring between each interval, until completely melted and smooth—this usually takes 1-2 minutes total.

The key is not to overheat, which can scorch the chocolate.

Step 3: Create the Wet Ingredient Base

• melted chocolate and butter mixture from Step 2
• 1 cup sugar
• 3 eggs
• 1 1/2 tsp vanilla

Add sugar to the melted chocolate mixture from Step 2 and stir well to combine.

Add room temperature eggs one at a time, stirring thoroughly after each addition—this helps them incorporate smoothly and build a cohesive batter.

Stir in the vanilla extract until fully mixed.

I like to use room temperature eggs because they blend more evenly into the batter, creating a smoother texture.

Step 4: Prepare Dry Ingredients and Combine

• wet ingredient base from Step 3
• 2/3 cup flour
• 1/4 cup cocoa
• 1/2 tsp instant espresso powder
• 1/2 tsp salt
• 1 cup zucchini
• 1 cup chocolate chips

In a separate small bowl, whisk together flour, cocoa powder, instant espresso powder, and salt—this distributes the espresso powder evenly throughout the batter and prevents cocoa clumps.

Fold the dry mixture into the wet ingredients from Step 3 until just combined, then gently fold in the shredded zucchini and 1 cup chocolate chips.

Don’t overmix; stop as soon as you don’t see streaks of flour.

Step 5: Bake the Bars

• batter from Step 4
• 2 tbsp chocolate chips
• 1 pinch flaky sea salt

Pour the batter into your prepared pan from Step 1 and smooth the top gently.

Scatter the 2 tablespoons of chocolate chips over the surface and finish with a light pinch of flaky sea salt—the salt enhances the chocolate flavor and adds a subtle sophistication.

Bake for 25 minutes, until a toothpick inserted in the center comes out with just a few moist crumbs (not completely dry, as these bars should be fudgy).

Step 6: Cool and Slice

Remove the pan from the oven and let the bars cool completely in the pan on a wire rack—this helps them set properly and makes slicing much easier.

Once fully cooled, cut into squares and serve.

I find waiting until they’re completely cool prevents crumbling and gives you cleaner, more attractive pieces.

Easy Double Chocolate Zucchini Bars

Delicious Easy Double Chocolate Zucchini Bars recipe with step-by-step instructions.

Print Recipe Pin Recipe

Prep Time 15 minutes mins

Cook Time 30 minutes mins

Total Time 45 minutes mins

Servings: 16 pieces

Calories: 2500

Ingredients Method

Ingredients

  

For the batter::

• 4.5 oz chocolate bar (I use Ghirardelli 60% Cacao semi-sweet baking bars)
• 1/2 cup butter (I like Kerrygold unsalted butter for this)
• 1 cup sugar
• 3 eggs (room temperature, about 70°F)
• 1 1/2 tsp vanilla
• 2/3 cup flour (I always use King Arthur all-purpose flour)
• 1/4 cup cocoa
• 1 cup chocolate chips
• 1 cup zucchini (finely shredded and squeezed dry of excess moisture)
• 1/2 tsp salt
• 1/2 tsp instant espresso powder

For the topping::

• 2 tbsp chocolate chips
• 1 pinch flaky sea salt

Method

 

1. Heat your oven to 320°F and grease a 9x13 inch baking dish (or 8x8 inch for thicker bars). I recommend using parchment paper for easy removal after baking.
2. Chop the 4.5 oz chocolate bar into small pieces and combine with butter in a microwave-safe bowl. Microwave in 30-second intervals, stirring between each interval, until completely melted and smooth—this usually takes 1-2 minutes total. The key is not to overheat, which can scorch the chocolate.
3. Add sugar to the melted chocolate mixture from Step 2 and stir well to combine. Add room temperature eggs one at a time, stirring thoroughly after each addition—this helps them incorporate smoothly and build a cohesive batter. Stir in the vanilla extract until fully mixed. I like to use room temperature eggs because they blend more evenly into the batter, creating a smoother texture.
4. In a separate small bowl, whisk together flour, cocoa powder, instant espresso powder, and salt—this distributes the espresso powder evenly throughout the batter and prevents cocoa clumps. Fold the dry mixture into the wet ingredients from Step 3 until just combined, then gently fold in the shredded zucchini and 1 cup chocolate chips. Don't overmix; stop as soon as you don't see streaks of flour.
5. Pour the batter into your prepared pan from Step 1 and smooth the top gently. Scatter the 2 tablespoons of chocolate chips over the surface and finish with a light pinch of flaky sea salt—the salt enhances the chocolate flavor and adds a subtle sophistication. Bake for 25 minutes, until a toothpick inserted in the center comes out with just a few moist crumbs (not completely dry, as these bars should be fudgy).
6. Remove the pan from the oven and let the bars cool completely in the pan on a wire rack—this helps them set properly and makes slicing much easier. Once fully cooled, cut into squares and serve. I find waiting until they're completely cool prevents crumbling and gives you cleaner, more attractive pieces.