1/2 c. skim milk
1/8 tsp. cream of tartar
2 tsp. sugar (opt.)
1/2 c. non fat dried milk powder
4 tsp. lemon juice
1/2 tsp. vanilla extract (opt.)

Put skim milk in small metal bowl, sit in the freezer and let stand until ice crystals begin to form, about 15 minutes. Remove from freezer and add dry milk powder and cream of tartar. With electric mixer, whip the mixture at high speed until foamy. Beat in 1 teaspoon lemon juice and continue beating until the mixture begins to thicken.