Fruit
Unflavored gelatin
Low-calorie sweetener

Puree your choice of fresh or frozen fruit in a blender, food processor or food mill. Bring the puree to a simmer on low heat, then stir in 1 teaspoon unflavored gelatin that has been softened in 1 tablespoon cold water for each cup of puree. Stir and simmer until gelatin is thoroughly dissolved. If desired, add non-calorie sweetener to taste. Chill until thickened. Refrigerate in covered container and use it within two weeks.