Mix together well with electric mixer and store in tight container in freezer. To make individual servings, place 1 heaping Tablespoon of mixture in mug with very hot water and a shot of rum. Stir. Top with whipped cream (Readi-Whip is fine). Mixture keeps indefinitely in freezer and can be easily spooned while frozen. Makes a cool whip size bowl worth of mixture, enough for many mugs of drink.