PREHEAT oven to 325°F. Mix peanut butter, sugar and egg until well blended. Refrigerate 30 min. Roll peanut butter mixture into 18 balls. Place, 2 inches apart, on ungreased baking sheet. Flatten each ball, in a criss-cross pattern, with fork.
BAKE 18 to 20 min. or until lightly browned. Cool 5 min. Remove from baking sheet to wire rack; cool completely.
DIP each end of cookie into melted chocolate, shaking off excess. Dip into chopped peanuts. Place cookies on parchment or wax-paper covered baking sheet. Refrigerate until chocolate hardens.
serving size = 1 cookie