1cupplus 2 tablespoons (200 g) good quality bittersweet chocolate, chopped or chocolate chips
½cup(113 g or 1 stick) unsalted butter, cut into quarters
3tablespoons(18 g) unsweetened cocoa powder
½teaspoonespresso powder, or instant coffee (optional)
3large eggs, room temperature
1 ¼cups(250 g) granulated sugar
2teaspoonspure vanilla extract
½teaspoonsalt
1cup(125 g) all-purpose flour
1cup(170 g or 6 oz) coarsely chopped peanut butter cups
Peanut Butter Frosting
⅔cup(150 g) creamy peanut butter
6Tbs(85 g) unsalted butter, room temperature
1cup(120 g) confectioners' sugar, sifted
½teaspoonvanilla extract
1Tablespoonmilk
Instructions
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.
Notes
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.