CHOCOLATE PEANUT BUTTER SWIRL CUPCAKES

Ingredients

• 2/3 cup all-purpose flour
• 1/2 tsp. baking powder
• 1/4 tsp. salt
• 1/2 cup (1 stick) unsalted butter, cut into small pieces
• 4 ounces semisweet chocolate, chop coarsely
• 2 ounces unsweetened chocolate, chop coarsely
• 3/4 cup granulated sugar
• 3 large eggs
• 2 tsp. pure vanilla extract

Peanut Butter Filling

• 4 Tbsp. (1/2 stick) unsalted butter, melted and cooled
• 1/2 cup confectioners' sugar, sifted
• 3/4 cup creamy peanut butter
• 1/4 tsp. salt
• 1/2 tsp. pure vanilla extract

Directions
1. Preheat oven to 325 degrees F.
2. Line cupcake pan with paper liners.
3.  Whisk together flour, baking powder, and salt; set aside.
4. Put butter and chocolates in a heatproof bowl and set over (not in) a pan of simmering water; stir until melted. Remove from heat and let cool slightly.
5. Whisk granulated sugar into cooled chocolate mixture.
6. Add the eggs, whisk until mixture is smooth.
7. Stir in the pure vanilla extract, then add the flour mixture. Stir until well blended.
8. In a separate bowl, combine all of peanut butter filling ingredients and stir until smooth.
9. Spoon 2 tablespoons of the chocolate batter into each lined cup. Place 1 tablespoon of the peanut butter filling on top. Put an additional tablespoon of the chocolate batter over the peanut butter filling layer.  Swirl 1 teaspoon of the peanut butter filling with the top layer of chocolate batter with a toothpick or wood skewer. [note: reduce amounts for mini cupcakes]
10. Bake, rotating pan halfway through, until a cake tester inserted in center comes out with just a few moist crumbs attached, about 40 minutes [15 –20 minutes for mini cupcakes].
11. Transfer pan to a wire rack to cool completely before removing cupcakes.

Source: from Martha Stewart Cupcakes