1In medium bowl, stir cookie mix, flour, butter and egg until dough forms. Shape dough into a ball; flatten slightly. Wrap dough in plastic wrap; refrigerate 1 hour or until firm.
2Heat oven to 375°F. Unwrap dough. On lightly floured surface, roll dough to 1/4-inch thickness. Cut with 3-inch tombstone-shaped cookie cutter. On ungreased cookie sheet, place cutouts 2 inches apart. Insert craft stick halfway into center of each cookie.
3Bake 10 to 12 minutes or until edges are lightly browned. Cool 5 minutes; remove from cookie sheet to cooling rack. Cool completely.
4Spread chocolate frosting on cookies. Attach plain tip to tube of green icing; pipe grass along bottom edge of tombstones. Remove plain tip from green icing; attach to tube of white icing. Pipe RIP in center of each tombstone.