Preheat oven to 325˚F. Line standard muffin tin with paper liners. Whisk together flour, baking powder, and salt. Put butter and chocolates in a heatproof bowl set over (not in) a pan of simmering water; stir until melted. Remove from heat, and let cool slightly.

Whisk granulated sugar into cooled chocolate mixture. Add eggs, and whisk until mixture is smooth. Stir in vanilla. Add flour mixture; stir until well incorporated.

Spoon 2 tablespoons chocolate batter into each lined cup, followed by 1 tablespoon peanut butter filling. Repeat with another tablespoon of batter, and top with 1 teaspoon filling. Swirl top of cupcake batter and filling with a wooden skewer or toothpick.

Bake, rotating tin halfway through, until a cake tester inserted in centers comes out with only a few moist crumbs attached, about 40 minutes. Transfer tin to a wire rack to cool completely before removing cupcakes. Cupcakes can be stored up to 3 days at room temperature in airtight containers.

Peanut-Butter Filling:

4 tablespoons (1/2 stick) unsalted butter, melted

1/2 cup confectioners’ sugar, sifted

3/4 cup smooth peanut butter

1/4 teaspoon salt

1/2 teaspoon pure vanilla extract

Stir together all ingredients until smooth. Use immediately.

Notes: Recipe only makes 12 – I recommend a double batch! Also, the timing was way off for my oven. 25 minutes baking time is all I needed for a double batch.

Recipe from: Martha Stewart’s Cupcakes