If you’re a chocolate lover with a penchant for peanut butter, you’re in for a treat! These Fudgy Peanut Butter Swirl Brownies are the perfect combination of rich, chocolatey goodness and creamy, nutty delight. Imagine biting into a gooey brownie, only to discover luscious swirls of peanut butter throughout. This recipe is not only easy to make but also incredibly satisfying, making it a go-to for any occasion. Whether you’re hosting a gathering or simply craving something sweet, these brownies will surely impress!
Why I Love This Recipe

There’s something extraordinary about the fusion of chocolate and peanut butter. The richness of the fudgy brownies pairs beautifully with the creamy peanut butter, creating a dessert that’s both decadent and comforting. Additionally, this recipe is straightforward, requiring minimal prep time while delivering maximum flavor. Plus, the swirls make each brownie visually appealing, making them a perfect addition to any dessert table.
What You’ll Gather

- 4 ounces (113g) unsweetened baking chocolate, coarsely chopped
- 1 cup (170g) unsalted butter
- 1 1/2 cups (300g) granulated sugar
- 1 teaspoon salt
- 3 large eggs
- 1 teaspoon vanilla extract
- 2 tablespoons (10g) Dutch-process cocoa powder (or regular unsweetened)
- 1 cup (124g) all-purpose flour
- 1 cup (133g) peanut butter
- 2 tablespoons (28g) unsalted butter, melted
- 1 cup (38g) powdered sugar
- 1 teaspoon vanilla extract
Before You Start: Equipment

- 9×9-inch baking pan – Perfect for baking the brownies. Line it with parchment paper for easy removal.
- Mixing bowls – Essential for combining ingredients efficiently.
- Whisk – For beating eggs and mixing batter thoroughly.
- Rubber spatula – Great for folding in ingredients and scraping down the sides of the bowl.
- Double boiler (or microwave) – Useful for melting chocolate and butter together smoothly.
Step-by-Step: Fudgy Peanut Butter Swirl Brownies
Step 1: Preheat Your Oven
Start by preheating your oven to 350°F (175°C). This ensures that your brownies bake evenly.
Step 2: Melt the Chocolate and Butter
In a double boiler or a microwave-safe bowl, combine the coarsely chopped unsweetened baking chocolate and 1 cup of unsalted butter. Heat gently until melted and smooth, stirring occasionally to avoid burning.
Step 3: Mix the Sugar and Eggs
In a large mixing bowl, whisk together 1 1/2 cups of granulated sugar and 1 teaspoon of salt. Add in the 3 large eggs and 1 teaspoon of vanilla extract, whisking until the mixture is light and fluffy.
Step 4: Combine Chocolate Mixture
Once your chocolate and butter mixture is melted and slightly cooled, pour it into the sugar and egg mixture. Stir until fully combined.
Step 5: Add Dry Ingredients
Sift in the 2 tablespoons of cocoa powder and the 1 cup of all-purpose flour. Use a spatula to fold these dry ingredients into the wet mixture until just combined. Be careful not to overmix!
Step 6: Prepare the Peanut Butter Swirl
In a separate bowl, combine 1 cup of peanut butter, 2 tablespoons of melted unsalted butter, 1 cup of powdered sugar, and 1 teaspoon of vanilla extract. Mix until smooth and creamy.
Step 7: Assemble the Brownies
Pour half of the brownie batter into the prepared baking pan, spreading it evenly. Then, dollop spoonfuls of the peanut butter mixture over the brownie batter. Pour the remaining brownie batter on top and swirl the peanut butter mixture using a knife or skewer for that marbled effect.
Step 8: Bake
Bake in the preheated oven for 25-30 minutes, or until a toothpick inserted into the center comes out with a few moist crumbs. Avoid overbaking for that fudgy texture.
Step 9: Cool and Slice
Allow the brownies to cool in the pan for about 20 minutes before lifting them out using the parchment paper. Let them cool completely on a wire rack before slicing into squares.
Seasonal Flavor Boosts
- Add a pinch of cinnamon for a warm, cozy flavor.
- Incorporate chopped nuts like walnuts or pecans for added crunch.
- Swirl in some caramel sauce for an extra indulgent treat.
- Sprinkle sea salt on top before baking for a sweet and salty finish.
Easy-to-Miss Gotchas
Here are a few tips to ensure your Fudgy Peanut Butter Swirl Brownies turn out perfect:
- Make sure your butter and chocolate mixture is not too hot when you add it to the eggs, as this can cause the eggs to scramble.
- Use room temperature eggs for better incorporation into the batter.
- Don’t overmix the brownie batter after adding the flour; a few lumps are okay!
- Check your brownies a few minutes before the suggested baking time to avoid overbaking.
Cooling, Storing & Rewarming
For the best texture, let your brownies cool completely before slicing. Store them in an airtight container at room temperature for up to 3 days or in the refrigerator for up to a week. If you want to enjoy them warm, simply pop them in the microwave for about 10-15 seconds before serving.
Popular Questions
Can I use dark chocolate instead of unsweetened chocolate?
Absolutely! Using dark chocolate will add a richer flavor to your brownies. Just adjust the sugar slightly if you prefer them less sweet.
Can I make these brownies in advance?
Yes, these brownies can be made a day ahead of time. In fact, they often taste even better the next day as the flavors meld together!
Can I freeze the brownies?
Definitely! To freeze, wrap the brownies tightly in plastic wrap and then place them in an airtight container. They can be frozen for up to 3 months. Thaw them at room temperature before enjoying.
What’s the best way to cut brownies?
To achieve clean cuts, use a sharp knife and wipe it clean between cuts. This prevents the brownies from crumbling and helps maintain their beautiful swirls.
Bring It to the Table
There’s no denying that these Fudgy Peanut Butter Swirl Brownies will become a staple in your dessert repertoire. With their rich chocolate flavor and creamy peanut butter, they are sure to satisfy any sweet tooth. Whether you’re a novice baker or a seasoned pro, this recipe is straightforward enough for anyone to master. So gather your ingredients, roll up your sleeves, and enjoy the process of creating something delicious!
Creating memories in the kitchen is what it’s all about. So, share these brownies with friends and family, and watch as they disappear in no time. Happy baking!

Fudgy Peanut Butter Swirl Brownies
Ingredients
- 4 ounces unsweetened baking chocolate coarsely chopped
- 1 cup unsalted butter
- 1 1/2 cups granulated sugar
- 1 teaspoon salt
- 3 large eggs
- 1 teaspoon vanilla extract
- 2 tablespoons Dutch-process cocoa powder or regular unsweetened
- 1 cup all-purpose flour
- 1 cup peanut butter
- 2 tablespoons unsalted butter melted
- 1 cup powdered sugar
- 1 teaspoon vanilla extract
Instructions
- Step 1: Preheat Your Oven. Start by preheating your oven to 350°F (175°C). This ensures that your brownies bake evenly.
- Step 2: Melt the Chocolate and Butter. In a double boiler or a microwave-safe bowl, combine the coarsely chopped unsweetened baking chocolate and 1 cup of unsalted butter. Heat gently until melted and smooth, stirring occasionally to avoid burning.
- Step 3: Mix the Sugar and Eggs. In a large mixing bowl, whisk together 1 1/2 cups of granulated sugar and 1 teaspoon of salt. Add in the 3 large eggs and 1 teaspoon of vanilla extract, whisking until the mixture is light and fluffy.
- Step 4: Combine Chocolate Mixture. Once your chocolate and butter mixture is melted and slightly cooled, pour it into the sugar and egg mixture. Stir until fully combined.
- Step 5: Add Dry Ingredients. Sift in the 2 tablespoons of cocoa powder and the 1 cup of all-purpose flour. Use a spatula to fold these dry ingredients into the wet mixture until just combined. Be careful not to overmix!
- Step 6: Prepare the Peanut Butter Swirl. In a separate bowl, combine 1 cup of peanut butter, 2 tablespoons of melted unsalted butter, 1 cup of powdered sugar, and 1 teaspoon of vanilla extract. Mix until smooth and creamy.
- Step 7: Assemble the Brownies. Pour half of the brownie batter into the prepared baking pan, spreading it evenly. Then, dollop spoonfuls of the peanut butter mixture over the brownie batter. Pour the remaining brownie batter on top and swirl the peanut butter mixture using a knife or skewer for that marbled effect.
- Step 8: Bake. Bake in the preheated oven for 25-30 minutes, or until a toothpick inserted into the center comes out with a few moist crumbs. Avoid overbaking for that fudgy texture.
- Step 9: Cool and Slice. Allow the brownies to cool in the pan for about 20 minutes before lifting them out using the parchment paper. Let them cool completely on a wire rack before slicing into squares.
Equipment
- 9x9-inch baking pan
- Mixing Bowls
- Whisk
- Rubber spatula
- Double boiler or microwave
Notes
- Make sure your butter and chocolate mixture is not too hot when you add it to the eggs, as this can cause the eggs to scramble.
- Use room temperature eggs for better incorporation into the batter.
- Don’t overmix the brownie batter after adding the flour; a few lumps are okay!
- Check your brownies a few minutes before the suggested baking time to avoid overbaking.
