Spray a mold (like large tupperware) with cooking spray, then pour a layer of the white mix about a half-inch deep. Chill for about 20-30 minutes in the freezer.
Take the mold out of the freezer and gently touch to check firmness. If not yet firm, place back in the freezer for another five minutes. Once the jello is firm, pour about a half inch of red mix on top and place in freezer for 20-30 minutes.