PREHEAT oven to 350° F.
BEAT 1 cup sugar and butter in large mixer bowl until well mixed. Add cocoa, egg, vanilla extract, baking powder and baking soda; beat until well mixed. Gradually beat in flour. Shape dough into 1-inch balls. Roll in 2 tablespoons sugar. Place 2-inches apart on ungreased baking sheets.
BAKE for 9 to 11 minutes or until set. Immediately press 3 mints on top of each cookie. Remove to wire racks to cool completely.