Peanut Butter Frosting
1 cup powdered sugar
3/4 cup creamy peanut butter (do not use old-fashioned or freshly ground)
1/4 cup (1/2 stick) unsalted butter, room temperature
1/4 teaspoon vanilla extract
4 teaspoons (about) whipping cream (optional)
Chocolate shavings or chocolate sprinkles
Put powdered sugar and next 3 ingredients in medium bowl. Using electric mixer, beat until mixture is smooth, adding whipping cream by teaspoonfuls if frosting is too thick to spread.
Spread frosting in swirls over top of cupcakes.
Sprinkle with chocolate shavings or chocolate sprinkles. (Can be made 1 day ahead. Store in single layer in airtight container at room temperature.)