ADD boiling water to gelatin mix in large bowl; stir 2 min. until completely dissolved. Add raspberries; stir until thawed. Add enough ice to cold water to measure 2 cups. Add to gelatin; stir until ice is melted. Let stand 5 min. or until thickened.
POUR over cake cubes in 3-qt. bowl.
REFRIGERATE 1 hour or until gelatin is set. Top with COOL WHIP.