1Heat oven to 375°F. In medium bowl, stir cookie mix, butter, egg and flour until dough forms. Divide dough into thirds. Tint one-third red and one-third green with food colors; leave one-third plain. Keep dough covered tightly until ready to use.
2On floured surface, roll each third of dough until 1/8 inch thick. For round cookies, cut with 1 1/2-inch cookie cutter; for square cookies, cut into 1 1/2-inch squares using sharp knife. (Dip cutter or knife in flour for easier cutting.)
3On ungreased cookie sheet, place half the cookies 1 inch apart. Place 1 candy piece on center of each cookie; top with another cookie. Gently press edges together to seal, using tines of fork. To decorate before baking, sprinkle cookies with colored sprinkles, sugars or decors as desired.
4Bake 6 to 8 minutes or until edges are light brown. Cool 1 minute; remove from cookie sheet to wire rack. Cool completely, about 30 minutes. Decorate with gels as desired.