Fresh or frozen mamey pulp can be used. Rub fruit through sieve or put through a food mill to remove any fiber. Soak gelatin in cold water then dissolve in the boiling water. Add sugar and salt to fruit pulp, then add gelatin. Chill until the mixture thickens. Whip until light. Add whipped topping and fold into the mamey mixture. Freeze.
Variations: 2 teaspoons of lemon juice can be added to the pulp if desired, and/or a very small amount of powdered ginger can be used.