Ingredients

Makes 12

　　

For cupcakes

1 1/4 cups all-purpose flour

　　1 1/2 teaspoons baking powder

　　Rounded 1/4 teaspoon salt

　　1/2 cup smooth peanut butter

　　1/2 stick (1/4 cup) unsalted butter, softened

　　1/2 cup packed light brown sugar

　　1 large egg

　　1/2 teaspoon vanilla

　　2/3 cup whole milk

　　

For icing

1/3 cup heavy cream

　　4 ounces milk chocolate, finely chopped

　　1/3 cup chopped peanuts

　　

Special Equipment

a muffin tin with 12 (1/2-cup) muffin cups and paper liners

　　

Make cupcakes:

Step 1

Preheat oven to 350°F.

　　

Step 2

Whisk together flour, baking powder, and salt in a bowl.

　　

Step 3

Beat together peanut butter, butter, and brown sugar in a large bowl with an electric mixer at medium speed until blended, about 2 minutes. Add egg and vanilla and beat until fluffy, about 1 minute. Reduce speed to low and add flour mixture and milk alternately in batches, beginning and ending with flour mixture, then mix until just combined.

　　

Step 4

Divide batter among lined muffin cups (about two-thirds full) and bake in middle of oven until pale golden and a tester inserted in center of a cupcake comes out clean, 18 to 20 minutes. Turn cupcakes out onto a rack and cool completely.

　　

Make icing while cupcakes cool:

Step 5

Bring cream to a boil in a small saucepan, then pour over chocolate in a small bowl. Let stand 1 minute, then whisk until smooth.

　　

Step 6

To thicken icing to spreading consistency quickly, spread it on a metal baking sheet and chill until thick and glossy, about 5 minutes. Scrape icing back into bowl and stir until smooth. Spread icing on cupcakes and sprinkle with peanuts.