Cook Crust (1 day before). Heat oven at 275°. Grease 9 x 13 pan. Beat egg whites, cream of tartar and salt. Add sugar. Beat about 10 minutes or until frothy and stiff. (Taste to be sure sugar is dissolved). Spread into pan and bake for 60 minutes. Turn oven off and leave in oven over night.
Filling:
Mix cream cheese, sugar and vanilla. Add cool whip and marshmallows. Spread over meringue crust. Refrigerate for 12 hours.
Topping:
Mix topping ingredients and refrigerate. Spoon this topping over filling. Cut into squares before serving.