Force cottage cheese through a sieve, or pulse until creamy in a food processor or blender; set aside
In a medium saucepan, combine egg yolks, milk, sugar and salt. Cook over medium heat, stirring constantly, until mixture is thickened; remove from heat. In a small bowl, dissolve gelatin in water. Stir into the custard mixture. Stir in creamed cottage cheese and lemon juice.
In a large glass or metal mixing bowl, beat egg whites until stiff peaks form. Fold whites into cheese mixture. Pour filling into graham cracker crust. Chill for several hours in the refrigerator before serving.