These Peanut Butter Brownies are a decadent treat that combines rich, fudgy chocolate with creamy peanut butter swirls. Each bite offers a perfect balance of velvety texture and intense flavor, making them irresistible for any dessert lover. With just over an hour of total time, you can create a batch of 24 squares that are ideal for sharing or savoring slowly. The nutty aroma and gooey center will have your kitchen smelling like a bakery in no time.
Packed with 297 calories per serving, these brownies are indulgent yet satisfying, offering a delightful mix of sweetness and richness. The interplay of crunchy edges and soft, chewy middles ensures every square is a little piece of heaven. Whether you’re baking for a crowd or treating yourself, these brownies are a guaranteed crowd-pleaser that’s worth every minute of effort.
Ingredients for Peanut Butter Brownies
- Brownie Batter:
- ¾ cup (170 g) unsalted butter, cut into Tablespoon-sized pieces
- ½ cup (90 g) semisweet chocolate chips
- ½ cup (50 g) natural cocoa powder
- ½ cup (100 g) granulated sugar
- 1 cup (200 g) light brown sugar, firmly packed
- 2 large eggs + 1 egg yolk (room temperature preferred)
- 1 teaspoon vanilla extract
- ½ teaspoon salt
- 1 cup (125 g) all-purpose flour
- ⅓ cup (85 g) mini chocolate chips (optional)
- Peanut Butter Batter:
- ½ cup (113 g) unsalted butter, softened
- ½ cup (140 g) creamy peanut butter
- ½ cup (100 g) granulated sugar
- ½ cup (100 g) light brown sugar, firmly packed
- 1 large egg
- 1 teaspoon vanilla extract
- 1 ⅓ cups (167 g) all-purpose flour
- ½ teaspoon cornstarch
- ¼ teaspoon baking powder
- ½ teaspoon salt
- 1 Tablespoon milk
- ⅔ cup Reese’s Pieces (optional)
Step-by-Step Instructions
- Preheat the oven to 350°F (175°C). Spray a 9×13-inch glass baking dish with baking spray.
- Prepare the Brownie Batter:
- In a large microwave-safe bowl, combine butter and semisweet chocolate chips. Microwave in 20-second increments, stirring well between each, until melted and smooth.
- Add cocoa powder and sugars, stirring until well combined.
- Mix in eggs, egg yolk, vanilla extract, and salt.
- Stir in flour until just combined. Fold in mini chocolate chips, if using. Set aside.
- Prepare the Peanut Butter Batter:
- Using an electric mixer, cream together butter, peanut butter, and sugars until smooth and creamy.
- Add egg and vanilla extract, mixing until combined.
- In a separate bowl, whisk together flour, cornstarch, baking powder, and salt.
- Gradually add the flour mixture to the peanut butter mixture, stirring until just combined. Stir in milk.
- Fold in Reese’s Pieces, if using.
- Assemble the Brownies:
- Alternate dropping spoonfuls of brownie batter and peanut butter batter into the prepared pan.
- Use a knife to gently swirl the batters together for a marbled effect. Top with additional Reese’s Pieces, if desired.
- Bake for 35-40 minutes, or until a toothpick inserted in the center comes out clean or with a few moist crumbs (no wet batter).
- Cool completely in the pan before slicing and serving.
Swirl It Up: Perfecting the Marble Effect
To achieve that beautiful marbled look, alternate dropping spoonfuls of brownie and peanut butter batter into the pan. Use a knife to gently swirl the batters together, but don’t overmix—you want distinct streaks of both flavors. For extra flair, sprinkle a handful of Reese’s pieces on top before baking.
Storage Secrets: Keeping Brownies Fresh
Store your peanut butter brownies in an airtight container at room temperature for up to 3 days. For longer storage, wrap them tightly in plastic wrap and freeze for up to 2 months. To enjoy, simply thaw at room temperature or warm them in the microwave for 10-15 seconds.
Time-Saving Tips for Busy Bakers
Prep your ingredients ahead of time by measuring out the dry ingredients and chopping the butter the night before. If you’re short on time, skip the Reese’s pieces or use pre-measured chocolate chips. You can also use a hand mixer for both batters to speed up the mixing process.
Recipe Variations: Mix It Up!
Swap the Reese’s pieces for chopped peanuts, peanut butter cups, or even white chocolate chips for a different twist. If you’re feeling adventurous, add a pinch of cinnamon or espresso powder to the brownie batter for a deeper flavor profile. Gluten-free? Substitute the all-purpose flour with a 1:1 gluten-free blend.
Equipment Guidance: Tools for Success
A 9×13 glass baking dish works best for even baking, but a metal pan can also be used—just reduce the baking time by 5 minutes. Use a microwave-safe bowl for melting the butter and chocolate, and a stand mixer or hand mixer for creaming the peanut butter batter. Don’t forget a toothpick to test for doneness!
Peanut Butter Brownies
Ingredients
BROWNIE BATTER
- ¾ cup unsalted butter cut into Tablespoon-sized pieces
- ½ cup semisweet chocolate chips
- ½ cup natural cocoa powder
- ½ cup granulated sugar
- 1 cup light brown sugar firmly packed
- 2 large eggs + 1 egg yolk room temperature preferred
- 1 teaspoon vanilla extract
- ½ teaspoon salt
- 1 cup all-purpose flour
- ⅓ cup mini chocolate chips
PEANUT BUTTER BATTER
- ½ cup unsalted butter softened
- ½ cup creamy peanut butter
- ½ cup granulated sugar
- ½ cup light brown sugar firmly packed
- 1 large egg
- 1 teaspoon vanilla extract
- 1 ⅓ cups all-purpose flour
- ½ teaspoon cornstarch
- ¼ teaspoon baking powder
- ½ teaspoon salt
- 1 Tablespoon milk
- ⅔ cup Reeses pieces optional
Instructions
- Preheat oven to 350F (175C) and prepare a 9×13 glass baking dish¹ by spraying with baking spray.
- Prepare Brownie batter first:
- BROWNIE BATTER
- In a large, microwave-safe bowl, combine butter and ½ cup semisweet chocolate chips. Heat in 20-second increments (stirring well in between) until chocolate and butter are melted and mixture is smooth.
- Add cocoa powder and sugars and stir well.
- Stir in eggs, egg yolk, vanilla extract, and salt.
- Add flour and stir well. Stir in mini chocolate chips, if using. Set aside while you prepare peanut butter blondie batter.
- Peanut Butter Blondies
- Using an electric mixer or stand mixer, cream together butter, peanut butter, and sugars until creamy and well-combined.
- Add egg and vanilla extract and stir well.
- In a separate, medium-sized bowl, whisk together flour, cornstarch, baking powder, and salt.
- Gradually add flour mixture to peanut butter mixture and stir until well. Add milk and stir until ingredients are completely combined.
- Use a spoon or spatula to stir in Reese’s pieces candy pieces, if using.
- Alternate dropping heaping spoonfuls of brownie batter and peanut butter blondie batter into your prepared pan. Use a knife to swirl and make sure the batter is evenly distributed. Top with additional candy pieces, if desired.
- Transfer to 350F (175C) and bake for 35-40 minutes or until a toothpick inserted in the center comes out clean or with a few moist crumbs (no wet batter).
- Allow brownies to cool in pan before slicing and serving.