In a mixing bowl, beat egg whites, cream of tartar and vinegar until soft peaks form. Gradually beat in the sugar, 1 tablespoon at the time until stiff glossy peaks form. Whisk in cornstarch. Line baking sheet with parchment paper or greased foil; spread with meringue to make 9-inch circles, forming 1-inch high rounded rim. Bake in center of 250 degree oven for about one hour or until crisp. Turn oven off and let meringue dry one hour. Remove from oven and gently peel off paper. Place on serving plate.
ORANGE MOUSSE FILLING:
Sprinkle gelatin over 1/2 cup. of the orange juice. Set aside. In a heavy bottom non aluminum saucepan, whisk egg yolks lightly. Add rind, remaining juice, and sugar. Cook over medium heat, stirring constantly for 5 to 10 minutes or until thick enough to coat the back of spoon. Remove from heat. Stir in the gelatin mixture to dissolve. Cover and refrigerate for about 15 minutes or until slightly thickened. In a bowl, fold Cool whip or whipped cream into gelatin mixture until combined. spoon into meringue shell. Cover and refrigerate for about 30 minutes or until set.