Fudgy Peanut Butter Swirl Brownies
If you’re on the hunt for a decadent dessert that combines rich chocolate with the creamy goodness of peanut butter, look no further than these Fudgy Peanut Butter Swirl Brownies. They are the perfect blend of textures and flavors, with a dense, fudgy base swirled with velvety peanut butter. These brownies are sure to satisfy your sweet tooth and impress your friends and family. Let’s dive into this delicious recipe that will have you coming back for seconds (and maybe thirds!).
Top Reasons to Make Fudgy Peanut Butter Swirl Brownies

- Rich, chocolatey flavor that chocolate lovers will adore.
- Peanut butter swirls add a creamy texture and nutty taste.
- Quick to make with simple ingredients.
- Perfect for sharing at gatherings or enjoying with a cup of coffee.
- Fudgy texture is irresistible and pairs beautifully with a scoop of ice cream.
Ingredients at a Glance
- 4 ounces (113g) unsweetened baking chocolate, coarsely chopped
- 1 cup (170g) unsalted butter
- 1 ½ cups (300g) granulated sugar
- ½ 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
- â…“ cup (133g) peanut butter
- 2 tablespoons (28g) unsalted butter, melted
- ½ cup (38g) powdered sugar
- 1 teaspoon vanilla extract
What’s in the Gear List
- 8×8-inch baking pan: Perfect for brownies.
- Mixing bowls: For combining ingredients smoothly.
- Whisk and spatula: Essential for mixing and spreading.
- Double boiler or microwave-safe bowl: For melting chocolate and butter.
- Parchment paper: Helps with easy removal of brownies from the pan.
Step-by-Step: Fudgy Peanut Butter Swirl Brownies

Step 1: Preheat the Oven
Preheat your oven to 350°F (175°C). Grease your 8×8-inch baking pan or line it with parchment paper for easy removal.
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. Melt them together until smooth, stirring occasionally. Be careful not to overheat the chocolate.
Step 3: Mix the Brownie Batter
In a large mixing bowl, combine the melted chocolate mixture with 1 ½ cups of granulated sugar and ½ teaspoon of salt. Whisk until well combined. Add in the eggs, one at a time, mixing well after each addition. Stir in 1 teaspoon of vanilla extract.
Step 4: Add Dry Ingredients
Sift together 2 tablespoons of Dutch-process cocoa powder and 1 cup of all-purpose flour. Gradually fold this dry mixture into the wet ingredients until just combined. Be careful not to overmix; you want a fudgy texture.
Step 5: Prepare the Peanut Butter Swirl
In a separate bowl, mix together ⅓ cup of peanut butter, 2 tablespoons of melted unsalted butter, ½ cup of powdered sugar, and 1 teaspoon of vanilla extract until smooth and creamy.
Step 6: Assemble the Brownies
Pour the brownie batter into the prepared baking pan and spread it evenly. Drop spoonfuls of the peanut butter mixture over the brownie batter. Using a knife or a skewer, gently swirl the peanut butter into the brownie mixture to create a marbled effect.
Step 7: 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. Do not overbake, as this will make the brownies dry.
Step 8: Cool and Serve
Allow the brownies to cool in the pan for at least 15 minutes before lifting them out using the parchment paper. Cut into squares and enjoy your Fudgy Peanut Butter Swirl Brownies!
Ingredient Swaps & Substitutions

- Unsweetened baking chocolate: You can use semi-sweet chocolate if you prefer a sweeter brownie.
- Granulated sugar: Coconut sugar can be used for a healthier option.
- All-purpose flour: Substitute with gluten-free flour for a gluten-free version.
- Peanut butter: Almond butter or cashew butter can be used for a different flavor.
What I Learned Testing
- Finding the right balance of chocolate and peanut butter is key to achieving the perfect flavor.
- Allowing the brownies to cool completely enhances their fudgy texture.
- Swirling the peanut butter in carefully creates beautiful marbling without overmixing.
- These brownies taste even better the next day as the flavors meld.
Refrigerate, Freeze, Reheat
These Fudgy Peanut Butter Swirl Brownies can be stored in an airtight container in the refrigerator for up to one week. For longer storage, freeze the brownies in a single layer on a baking sheet, then transfer them to a freezer-safe container for up to three months. To reheat, simply microwave for a few seconds or enjoy them at room temperature.
FAQ
Can I use a different type of nut butter?
Absolutely! Almond butter, cashew butter, or even sunflower seed butter can be great alternatives if you’re looking for a different flavor profile or have nut allergies.
How do I know when the brownies are done baking?
The brownies are done when a toothpick inserted into the center comes out with a few moist crumbs attached. Be careful not to overbake, or they may lose their fudgy texture.
Can I make these brownies ahead of time?
Yes, you can make these brownies a day or two in advance. They actually taste better after resting for a bit as the flavors meld together.
What can I serve with these brownies?
These brownies are delicious on their own, but they pair wonderfully with vanilla ice cream, whipped cream, or a drizzle of chocolate sauce for an extra special treat.
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Let’s Eat
Indulging in these Fudgy Peanut Butter Swirl Brownies is a delightful experience that promises to satisfy your chocolate cravings. The rich, fudgy texture combined with the creamy peanut butter swirls creates a dessert that is both comforting and indulgent. Whether you’re making these brownies for a special occasion or simply to treat yourself after a long day, they’re sure to impress. Happy baking!

Fudgy Peanut Butter Swirl Brownies
Ingredients
Equipment
Method
- Preheat your oven to 350°F (175°C). Grease your 8x8-inch baking pan or line it with parchment paper for easy removal.
- In a double boiler or a microwave-safe bowl, combine the coarsely chopped unsweetened baking chocolate and 1 cup of unsalted butter. Melt them together until smooth, stirring occasionally. Be careful not to overheat the chocolate.
- In a large mixing bowl, combine the melted chocolate mixture with 1 ½ cups of granulated sugar and ½ teaspoon of salt. Whisk until well combined. Add in the eggs, one at a time, mixing well after each addition. Stir in 1 teaspoon of vanilla extract.
- Sift together 2 tablespoons of Dutch-process cocoa powder and 1 cup of all-purpose flour. Gradually fold this dry mixture into the wet ingredients until just combined. Be careful not to overmix; you want a fudgy texture.
- In a separate bowl, mix together ⅓ cup of peanut butter, 2 tablespoons of melted unsalted butter, ½ cup of powdered sugar, and 1 teaspoon of vanilla extract until smooth and creamy.
- Pour the brownie batter into the prepared baking pan and spread it evenly. Drop spoonfuls of the peanut butter mixture over the brownie batter. Using a knife or a skewer, gently swirl the peanut butter into the brownie mixture to create a marbled effect.
- Bake in the preheated oven for 25-30 minutes or until a toothpick inserted into the center comes out with a few moist crumbs. Do not overbake, as this will make the brownies dry.
- Allow the brownies to cool in the pan for at least 15 minutes before lifting them out using the parchment paper. Cut into squares and enjoy your Fudgy Peanut Butter Swirl Brownies!
Notes
- For a sweeter brownie, substitute unsweetened chocolate with semi-sweet chocolate.
- Store brownies in an airtight container in the refrigerator for up to one week.
- These brownies taste even better the next day as the flavors meld.
