Heat oven to 350°F.
On ungreased cookie sheets, place 12 cookies 3 inches apart for puppy faces. Cut remaining 12 cookies in half; place 2 halves on sides of each whole cookie for ears. Bake 9 to 13 minutes or until golden brown. Cool 2 minutes on cooking sheets. Remove to cooling racks. Cool completely, about 15 minutes.
Frost puppy face with white frosting and ears with chocolate frosting. Decorate each puppy with heart shapes for eyes and nose. Spoon remaining chocolate frosting into small resealable food-storage plastic bag. Cut off tiny corner. Pipe each mouth using chocolate frosting. Store loosely covered.