Grease the sides of a 1-1/2-quart souffle dish with butter or margarine. Sprinkle the sides of the dish with a little sugar; set aside. Stir together the applesauce, apple brandy or juice, and lemon juice in a small mixing bowl; set aside.
Melt 2 tablespoons butter or margarine in a small saucepan. Stir in flour. Add milk all at once. Cook and stir over medium heat until thickened and bubbly. Remove from heat. Gradually stir the hot mixture into the beaten egg yolks. Stir in the applesauce mixture; set aside.
Beat egg whites and vanilla in a large mixing bowl with an electric mixer on medium speed until soft peaks form (tips curl). Gradually add 1/4 cup sugar, about 1 tablespoon at a time, beating on medium to high speed until stiff peaks form (tips stand straight). Fold about 1 cup of the beaten egg white mixture into applesauce mixture. Fold applesauce mixture into remaining beaten egg white mixture. Carefully transfer to the prepared dish.
Bake in the preheated oven about 35 minutes or until a knife inserted near the center comes out clean. Serve at once. Makes 6 servings.