1. Prepare cookies according to recipe directions. Cool completely.
2. Place chocolate cookie flat side up on paper towel; top with two chocolate pieces. Place marshmallow half on top of chocolate.
3. Microwave at MEDIUM (50%) in 10 second intervals until marshmallow puffs. Top with matching cookie; press down slightly. Repeat with remaining cookies. Decorate with frosting, if desired. Makes 18 cookies.