Heat oven to 350°F. In medium bowl, stir baking mix, powdered sugar, butter, egg and drink mix (dry) until dough forms. Pat mixture firmly on bottom of ungreased 8-inch square pan.
Bake 14 to 18 minutes or until lightly browned around edges. Cool in pan on wire rack about 1 hour.
Spread bars with frosting; sprinkle with candies. For bars, cut into 5 rows by 5 rows.