In small bowl, reserve 1 cup frosting. Frost cupcakes with remaining white frosting. Stir pink food color into reserved 1 cup white frosting until desired pink color. Spoon frosting into freezer plastic bag; cut 1/4-inch hole in 1 bottom corner. Or use decorating bag with flat tip with 1/4-inch wide opening (#44). Gently squeeze bag to pipe frosting ribbon on cupcakes. Store loosely covered.