1In large bowl, stir first five ingredients until soft dough forms. Divide dough in half. Wrap in plastic wrap; refrigerate 2 hours.
2Heat oven to 375°F. Unwrap dough; on lightly floured surface, roll half of dough to 1/4-inch thickness. Cut with floured 5-inch Christmas tree-shaped cookie cutter. On ungreased cookie sheets, place cutouts 2 inches apart. Repeat with remaining half of dough. Bake 8 to 10 minutes or until edges are set. Cool 2 minutes; remove from cookie sheets to cooling racks. Cool completely, about 30 minutes.
3Mix vanilla frosting and green paste food color until blended. Spread on cookies. Spread chocolate frosting on base of each cookie for tree stump. With white icing, starting at the top, pipe thin swooping lines to look like light strands. Decorate with light bulb candy sprinkles. Place star candy sprinkle at top of each cookie. Let stand until set.