Heat oven to 375°F. In medium bowl, mix cookie mix, butter, flour and egg until soft dough forms. On lightly floured surface, roll dough 1/4 inch thick.
Using 5-inch Christmas tree cookie cutter, cut dough. (Reroll dough after cutting cookies to make 18 trees.) Place on ungreased cookie sheet.
Bake 6 to 8 minutes (8 to 10 minutes for large cookies) or until edges are light golden brown.
Meanwhile, unroll and remove paper from Betty Crocker Fruit Roll-Ups. Cut in half, separating blue and green. Using same cookie cutter, cut 5-inch tree shapes (if using larger cookie cutter, put two green halves together before cutting out tree shape. Place over warm cookies. Cut additional fruit snacks with kitchen scissors to use as garland, stars or ornaments. Frost with frosting as desired. Decorate with Betty Crocker Fruit Gushers to look like ornaments on trees.