Peanut Butter Swirl Brownies

Peanut Butter Swirl Brownies are the ultimate treat for lovers of the rich, bold flavor of chocolate combined with the nutty, creamy goodness of peanut butter. These decadent bars combine a chewy, fudgy brownie base with luscious ribbons of peanut butter swirled throughout, creating a beautifully marbled effect and a perfect balance of salty and sweet in every bite. The contrast of textures—dense chocolate with creamy peanut butter—and the satisfying harmony of flavors make these brownies an all-time favorite, whether you’re baking for a special occasion, a casual family dessert, or just to satisfy a weeknight craving. The peanut butter not only adds flavor but also lends a richness that elevates the entire experience, transforming a classic dessert into something more indulgent, more memorable, and endlessly crave-worthy. With simple ingredients and a straightforward method, these brownies offer gourmet appeal with minimal effort, making them a go-to recipe for home bakers of all skill levels.

The History of Peanut Butter Brownies

Brownies themselves are a proud part of American culinary history, first appearing in the late 1800s and becoming a mainstay in kitchens across the country by the early 20th century. Peanut butter, too, has a rich history in the United States, gaining popularity in the early 1900s as a protein-packed, shelf-stable food. The combination of peanut butter and chocolate rose to fame in candy form with the introduction of products like Reese’s in the 1920s. Naturally, home bakers began experimenting with these two beloved ingredients in other desserts, and peanut butter swirl brownies were born out of this sweet pairing. The concept likely started gaining traction in the 1970s and 1980s, when recipe books and baking magazines began encouraging creative add-ins and swirls to customize classic recipes. Since then, this variant has become a popular twist on traditional brownies, offering a modern yet nostalgic flavor profile that satisfies both the chocolate purist and the peanut butter enthusiast.

Ingredients Breakdown

To make the best Peanut Butter Swirl Brownies, it’s important to start with quality ingredients and understand how each one contributes to the final result. Unsalted butter provides richness and moisture, forming the base of a fudgy brownie texture. Granulated sugar sweetens and helps create the shiny, slightly crackly top. You can also use brown sugar for added depth and moisture. High-quality dark chocolate or a mix of cocoa powder and chocolate chips gives the brownies their intense chocolate flavor. All-purpose flour provides structure, and it’s important not to overuse it if you want to avoid a cakey texture. Salt enhances the chocolate flavor and balances sweetness. Eggs, including sometimes an extra yolk, bind the ingredients and contribute to that chewy, rich consistency. Vanilla extract brings aromatic depth to the batter. For the swirl, you’ll need creamy peanut butter—natural or commercial brands work, but the consistency of shelf-stable peanut butter tends to swirl better. A touch of powdered sugar or honey can be added to the peanut butter to thicken or sweeten it slightly, making it easier to swirl and better integrated with the brownie batter.

Step-by-Step Recipe

1. Preheat your oven to 175°C (350°F) and line an 8×8-inch (20×20 cm) square baking pan with parchment paper, leaving a bit of overhang on the sides for easy removal.
2. Melt the butter and chocolate together in a heatproof bowl set over a pan of simmering water or microwave in short bursts, stirring until smooth. Let the mixture cool slightly.
3. In a large mixing bowl, whisk together the sugar and eggs until well combined and slightly thickened. Stir in the vanilla extract.
4. Add the cooled chocolate mixture to the egg and sugar mixture, whisking until smooth.
5. Sift in the flour, cocoa powder, and salt, then gently fold the dry ingredients into the wet ingredients using a spatula until just combined—don’t overmix.
6. In a separate small bowl, combine the peanut butter with a little powdered sugar or honey if desired, to make it slightly thicker and more swirlable.
7. Pour the brownie batter into the prepared pan, spreading it evenly. Drop spoonfuls of the peanut butter mixture over the top of the batter.
8. Use a butter knife or skewer to gently swirl the peanut butter into the batter, creating a marbled pattern. Be careful not to over-swirl—you want distinct ribbons of peanut butter throughout.
9. Bake for 28 to 32 minutes, or until the edges are set and a toothpick inserted in the center comes out with a few moist crumbs.
10. Cool in the pan for at least 20–30 minutes before lifting out and cutting into squares. For the cleanest cuts, cool completely or chill briefly before slicing.

Tips for the Perfect Peanut Butter Swirl Brownies

1. Use room temperature eggs—they mix better and help the batter emulsify properly.
2. Don’t overbake—brownies continue to cook as they cool. Slightly underbaked is ideal for a fudgy center.
3. Use a commercial peanut butter like Jif or Skippy for the best swirl texture; natural peanut butter can be too oily or runny.
4. Warm the peanut butter slightly if it’s too thick, but don’t make it hot—just soft enough to swirl easily.
5. Cool completely before slicing to get clean edges and allow the flavors to set.
6. Add a sprinkle of flaky sea salt on top before baking for a sweet-salty finish that enhances both chocolate and peanut butter flavors.

Variations and Customizations

Peanut Butter Swirl Brownies are highly adaptable. You can fold chocolate chips or chopped peanut butter cups into the batter for extra decadence. Add a layer of graham cracker crust at the bottom for a s’mores-inspired version. Swirl in a bit of Nutella or dulce de leche alongside the peanut butter for a double-swirled brownie. For a crunchy contrast, top with chopped roasted peanuts or pretzels before baking. If you’re a fan of spice, stir a pinch of cayenne pepper or cinnamon into the batter for a warming kick. Make it gluten-free by using a 1:1 gluten-free flour blend, or dairy-free by using plant-based butter and chocolate. For a more festive presentation, add mini marshmallows or a drizzle of melted chocolate on top after baking. The options are endless, and each variation brings out a new dimension in the classic chocolate and peanut butter combination.

Health Considerations and Nutritional Value

While Peanut Butter Swirl Brownies are undeniably indulgent, understanding their nutritional profile can help you make informed choices. A typical square contains between 250–400 calories, with a notable amount of fat and sugar, primarily from butter, chocolate, and peanut butter. However, there are ways to make them slightly healthier without sacrificing flavor. Using natural peanut butter with no added sugar, cutting back slightly on sugar, or replacing a portion of the butter with applesauce, Greek yogurt, or mashed banana can reduce calories and saturated fat. Opting for dark chocolate with at least 70% cocoa content increases antioxidant benefits. You can also incorporate whole wheat flour or oat flour for extra fiber. For people with dietary restrictions, these brownies can be adapted to be gluten-free, dairy-free, or even vegan using suitable substitutions like flax eggs, dairy-free chocolate, and plant-based butter. As with any dessert, moderation is key—enjoying a small serving as part of a balanced diet is the best approach.

FAQ

Q: Can I use natural peanut butter for the swirl?
A: Yes, but it’s best to stir it well and slightly thicken it with powdered sugar or chill it first so it doesn’t sink into the batter or become greasy during baking.

Q: How do I store peanut butter brownies?
A: Store them in an airtight container at room temperature for up to 4 days, or refrigerate for up to a week. They also freeze well for up to 3 months.

Q: Why didn’t my swirl stay visible?
A: You may have over-swirlled or used peanut butter that was too thin. Use thick, creamy peanut butter and swirl gently just at the surface.

Q: Can I double this recipe?
A: Absolutely—double all ingredients and bake in a 9×13-inch pan. You may need to add 5–10 minutes to the baking time.

Q: Can I make these brownies ahead of time?
A: Yes, they actually taste better the next day as the flavors develop. Store covered at room temperature or refrigerate if you prefer a firmer texture.

Peanut Butter Swirl Brownies

Peanut Butter Swirl Brownies blend rich, fudgy chocolate with smooth, nutty peanut butter for a showstopping treat that’s as beautiful as it is delicious. With easy steps, customizable options, and an irresistible flavor pairing, they’re the perfect indulgence for any chocolate and peanut butter lover.

Print Recipe Pin Recipe

Prep Time 30 minutes mins

Cook Time 35 minutes mins

Total Time 1 hour hr 30 minutes mins

Servings 16

Ingredients

  

Brownie Batter:

• ½ cup 8 tablespoons or 113g salted butter *
• 8 ounces 228g quality semi-sweet chocolate, coarsely chopped *
• ¾ cup 150g granulated sugar
• ¼ cup 50g packed light brown sugar
• 3 large eggs
• 1 teaspoon pure vanilla extract
• ½ cup + 2 tablespoons 79g all-purpose flour, spooned and leveled
• 2 tablespoons 10g unsweetened cocoa powder
• ¼ teaspoon salt

Peanut Butter Filling:

• ¾ cup 185g creamy peanut butter
• 1 cup 120g confectioners’ sugar
• 2 teaspoons pure vanilla extract
• 2 tablespoons 30ml milk
• 2 tablespoons each of chocolate chips and peanut butter chips

Instructions

 

• Melt the butter and chopped chocolate together in a medium saucepan over medium heat, stirring constantly for about 5 minutes, until fully melted and smooth. Alternatively, you can melt them in a microwave-safe bowl using 20-second intervals, stirring after each burst, until smooth. Once melted, remove from heat and transfer the mixture to a large mixing bowl. Let it cool slightly for about 10 minutes.
• While the chocolate mixture is cooling, prepare the peanut butter filling. In a medium mixing bowl, using a handheld mixer or a stand mixer fitted with the paddle attachment, beat together the creamy peanut butter, confectioners’ sugar, vanilla extract, and milk on medium-high speed until well combined. The filling will be thick and resemble crumbly cookie dough. Set it aside.
• Position your oven rack in the lower third of the oven and preheat to 350°F (177°C). Line the bottom and sides of a 9-inch square baking pan with aluminum foil, leaving an overhang on all sides for easy removal. Set the prepared pan aside.
• Once the chocolate mixture has cooled, whisk in the granulated sugar and brown sugar until fully incorporated. Add the eggs one at a time, whisking well after each addition until the mixture is smooth. Stir in the vanilla extract. Gently fold in the flour, cocoa powder, and salt using a spatula, mixing just until combined.
• Pour and spread half of the brownie batter evenly into the prepared baking pan. Take chunks of the peanut butter filling, flatten them with your hands, and layer the flat pieces evenly over the brownie base. Spread the remaining brownie batter on top, smoothing the surface. Sprinkle the chocolate chips and peanut butter chips evenly over the top, then gently press them into the batter with the back of a spatula.
• Bake for 35–36 minutes, or until the edges begin to pull away from the sides of the pan. It’s normal for the center to crack slightly due to air trapped between the peanut butter layers. Use a toothpick to test doneness—the brownies are ready when it comes out with a few moist crumbs but no raw batter. Ovens vary, so start checking around the 30-minute mark.
• Allow the brownies to cool completely in the pan set on a wire cooling rack. Once cooled, lift them out of the pan using the foil overhang and cut into squares. For clean, neat cuts, use a very sharp knife and wipe it clean with a paper towel between slices.