Peanut Butter and Chocolate Cupcakes

Heat oven to 350°F. Line 24 muffin cups with paper liners.

Whisk flour, cocoa, baking soda and salt in medium bowl until well mixed. In small bowl, whisk milk and sour cream until blended.

Beat butter and sugar in large bowl with an electric mixer until creamed. Beat in peanut butter until blended. Add eggs, one at a time, until incorporated.

With mixer on low speed, alternately add flour mixture and milk mixture, beginning and ending with flour mixture, until just blended.

Spoon about 1/4 cup batter into each muffin cup. Bake 20 minutes or until wooden pick inserted in center comes out clean. Cool 10 minutes; remove cupcakes from pan to wire rack to cool completely.

Beat peanut butter and butter in medium bowl with electric mixer until smooth. On low speed, gradually beat in confectioners' sugar and 3 to 4 Tbsp milk until blended. Beat mixture on high speed 1 minute or until fluffy.

Spoon filling into a pastry bag fitted with a 1/4-in. plain round tip. Insert tip into the top of each cupcake; squeeze as much filling into the center of each as possible (top of cupcake will bulge slightly).

Melt chocolate chips in large glass bowl in microwave as package directs. Add sour cream; beat with an electric mixer until fluffy and good spreading consistency. Spread about 2 Tbsp frosting on each cupcake.