The dynamic duo are back in brownie form! Chocolate and peanut butter are meant to be together, especially when it comes to dessert bars. These super fudgy brownies have chopped peanut butter cups in the batter plus a creamy peanut butter frosting on top!

frosted peanut butter brownie with peanut butter cups inside.

I’ll be honest. When it comes to baking, peanut butter is not my go-to flavor (I much prefer chocolate recipes). However, when you add Reese’s to a dessert, I can’t say no! These fudgy peanut butter brownies are easy to make from scratch and have the perfect balance of rich chocolate-y flavor to creamy peanut butter. This recipe is a favorite of mine to share with friends!

Why You’ll Love This Recipe

  • The best combo. Peanut butter and chocolate together are simply the best!
  • Reliable recipe. I used my fudgy brownie recipe as the base. It’s been my go-to for years and it never fails!
  • Fudgy texture. Dense and chocolate-y, each bite is a treat for the tastebuds.
  • Plenty of flavor. Not only are these brownies topped with peanut butter frosting, but they also have chopped peanut butter cups in the batter!
  • Perfect for any occasion! Make these bars for birthday,s, Christmas, Valentine’s Day or simply because you’re craving a delicious dessert!

Ingredient Notes

bowls of ingredients for peanut butter brownies.
  • Chocolate: Use good-quality bittersweet chocolate, such as Ghirardelli or Bakers Chocolate. It melts more smoothly and tastes richer!
  • Cocoa powder: Use unsweetened cocoa powder. I prefer Ghirardelli, but Hershey’s works too.
  • Espresso powder: This optional ingredient enhances the chocolate flavor (it’s my favorite trick for chocolate desserts!)
  • Peanut butter cups: To add another layer of deliciousness, chop up some mini peanut butter cups and stir them into the batter!
  • Peanut butter: Use creamy, no-stir peanut butter for best results. I prefer Skippy All Natural.
  • Confectioners’ sugar: Also known as powdered sugar, this is used in the frosting.

Please refer to recipe card for measurements and ingredient details.

Recipe Variations

Try a different frosting or mix-in. For an extra layer of chocolate, frost the bars with chocolate buttercream instead. Other mix-ins include Reese’s pieces, peanut butter chips or chopped Butterfingers.

Add a swirl on top. After transferring the brownie batter into the pan, drop teaspoons of peanut butter on top. Use a knife or toothpick to swirl it into the batter (avoid over-mixing). Bake according to instructions.

Double the recipe and bake it in a 9×13 pan. Baking time will be approximately the same and you’ll get enough bars to serve a crowd!

How to Make Peanut Butter Brownies

photo collage demonstrating how to make peanut butter brownies in a mixing bowl.
  1. Melt the chocolate and butter in a make shift double boiler. Whisk in the cocoa powder and espresso powder (if using). Set aside to cool slightly.
  2. Mix eggs and sugar until pale and fluffy, about 1 minute. Mix in vanilla and salt. Add melted chocolate and mix just until combined. Scrape down the sides and bottom of the bowl as necessary.
  3. Stir in the flour just until combined, then stir in the chopped peanut butter cups.
  4. Transfer batter to a parchment-lined 8×8 baking pan. Bake at 350 F for 25 minutes. Cool completely.
photo collage demonstrating how to make peanut butter frosting for brownies.
  1. Make the frosting. Beat peanut butter and butter until smooth. Add confectioners’ sugar and mix until well combined. Add vanilla and milk, then mix until incorporated.
  2. Spread frosting over cooled brownies. Slice and serve.

Expert Tips

Weigh your ingredients using a kitchen scale. This guarantees accurate measurements. If you don’t have a scale, spoon and level your flour into a measuring cup.

Use good quality chocolate. This makes all the difference in taste when it comes to chocolate desserts. My go-to is Ghirardelli, but Guittard and Bakers chocolate are also good options. These higher qualities are also easier to melt.

Don’t over-bake the brownies! This is the secret to fudgy brownies. You want to take them out when the top is shiny and the edges are set. They will continue to bake as they cool.

Use creamy, no-stir peanut butter for the frosting. It will create a creamier, smoother texture. If there is oil sitting on top of the peanut butter in the jar, then it will be too liquid-y and create a poorly textured frosting.

Clean your knife after each cut. This will make nice clean bars for a beautiful presentation!

peanut butter brownies with frosting and peanut butter cups on parchment paper.

Make Ahead and Storage Tips

Make ahead: Bake the brownies 24 hours ahead of time. Keep them covered at room temperature before frosting. The peanut butter frosting may be made up to 3 days in advance. Store in the refrigerator and bring to room temperature before using.

Storage: Frosted brownies will keep at room temperature for up to 3 days or in the refrigerator for 5 days. Store in an airtight container to keep them fresh.

Freezing: After the brownies have completely cooled, wrap them in plastic wrap and aluminum foil to prevent freezer burn. Freeze for up to 3 months. If freezing with the frosting I suggest flash freezing for an hour so the frosting is firm before wrapping in plastic wrap. Defrost in the refrigerator before bringing to room temperature.

Recipe FAQ

How do you make brownies fudgy?

For a dense chocolate center, slightly under-bake the brownies. For an 8×8 pan, this usually takes about 25 minutes of baking time. Also make sure you’re weighing your ingredients properly. Too much flour will make the brownies dry and cake-like.

Can I swap out butter for peanut butter in brownies?

Yes, but you have to add oil too. For every 1/2 cup butter, substitute with 1/4 cup peanut butter and 1/4 cup oil.

Why are my brownies crumbly?

Most likely there was too much air in the batter, which can happen if the ingredients are over-mixed. Alternatively, the brownies were not completely cooled before slicing.

Can I use almond butter in this recipe?

Yes, you can substitute almond butter for peanut butter.

frosted peanut butter brownie with a bite taken off the corner.

Did you love this recipe? Please leave a 5-star 🌟🌟🌟🌟🌟 rating in the recipe card below and if you REALLY loved it, consider leaving a comment further down the page.

frosted peanut butter brownie with peanut butter cups inside.

Get the Recipe: Frosted Peanut Butter Brownies

These fudgy peanut butter brownies are easy to make from scratch and make the perfect dessert for any occasion!
5 (8 ratings)



  • 1 cup plus 2 tablespoons (200 g) good quality bittersweet chocolate, chopped or chocolate chips
  • ½ cup (113 g or 1 stick) unsalted butter, cut into quarters
  • 3 tablespoons (18 g) unsweetened cocoa powder
  • ½ teaspoon espresso powder, or instant coffee (optional)
  • 3 large eggs, room temperature
  • 1 ¼ cups (250 g) granulated sugar
  • 2 teaspoons pure vanilla extract
  • ½ teaspoon salt
  • 1 cup (125 g) all-purpose flour
  • 1 cup (170 g or 6 oz) coarsely chopped peanut butter cups

Peanut Butter Frosting

  • cup (150 g) creamy peanut butter
  • 6 Tbs (85 g) unsalted butter, room temperature
  • 1 cup (120 g) confectioners' sugar, sifted
  • ½ teaspoon vanilla extract
  • 1 Tablespoon milk


  • Preheat oven to 350° F. Line an 8 by 8-inch square baking pan with parchment paper and lightly grease with nonstick cooking spray. Set aside.
  • In a makeshift double boiler over low heat, melt chocolate and butter, stirring occasionally (see notes for microwave method). Remove pan from the heat and whisk in the cocoa and instant espresso. Set aside to cool slightly.
  • In the bowl of a stand mixer, beat together eggs and sugar on medium-high speed for 1 minute. Reduce speed to low and add vanilla and salt until combined, about 15 seconds. Keep mixer on low and slowly pour in chocolate mixture into the egg mixture.
  • Remove bowl from mixer and stir in the flour with a wooden spoon until just combined (do not over-mix). Stir in chopped peanut butter cups.
  • Pour the mixture into the prepared pan, spread into the corners and level with a rubber spatula. Bake 25 minutes, or until the top is shiny and the center is still dense. Brownies will continue to bake once removed from oven.
  • Cool on a wire rack to room temperature, about 2 hours. When ready to serve, prepare the frosting.
  • In the bowl of a stand mixer or using a hand mixer, beat peanut butter and butter until smooth. Add confectioners’ sugar and mix until well combined. Add vanilla and milk, then mix until incorporated. For a thinner frosting, add more milk, 1 teaspoon at a time, until desired consistency is reached.
  • Spread frosting over cooled brownies. Slice and serve.


Melting chocolate: I prefer the stovetop method, but you can also microwave on 50% power level and stop to stir every 20 seconds until the chocolate and butter are mostly melted.  
Peanut butter: Use no-stir creamy for best results (don’t use the kind where the oil separates and sits on top).
Store in an airtight container at room temperature for 3 days or in the refrigerator for 5 days.
Freeze frosted brownies for up to 3 month. Flash freeze for 1 hour so the frosting hardens, then wrap in plastic wrap and aluminum foil. Defrost in the refrigerator before bringing to room temperature and serving. 
Serving: 1brownie, Calories: 470kcal, Carbohydrates: 50g, Protein: 7g, Fat: 28g, Saturated Fat: 13g, Polyunsaturated Fat: 3g, Monounsaturated Fat: 10g, Trans Fat: 0.5g, Cholesterol: 63mg, Sodium: 203mg, Potassium: 232mg, Fiber: 3g, Sugar: 39g, Vitamin A: 416IU, Vitamin C: 0.1mg, Calcium: 38mg, Iron: 2mg

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