Place cauliflowerets in center of Reynolds Wrap(R) Heavy Duty Aluminum Foil. Spoon cheese sauce evenly over cauliflowerets; top with bell pepper and ice cubes. Sprinkle with salt and pepper, if desired. Place packet on baking sheet with 1-inch sides.
Bring up sides of foil; fold down two times. Double fold both ends of foil to seal packet, leaving room for heat circulation inside.
Bake 20 to 25 minutes or until cauliflowerets are at desired texture. Open packet carefully by cutting along top folds with a sharp knife, allowing steam to escape. Stir to coat evenly.