1. Sprinkle gelatin over 1/4 cup of the skim milk in small bowl; let stand for 5 minutes to soften.
2. In top of double boiler, beat egg yolks, sugar and remaining skim milk. Cook over simmering water, stirring constantly, until mixture thickens and lightly coats back of wooden spoon. Add softened gelatin and stir to dissolve. Remove from heat; stir in cottage cheese, lemon juice and vanilla extract.
3. Using electric mixer at high speed, beat egg whites in small bowl until stiff. Using rubber spatula, fold into cheese mixture along with whipped topping. Divide mixture among four 10-ounce custard cups; chill until completely set, about 1 hour.