Bake Jiffy cake at 350 degrees for 15 minutes (according to directions on box); but put in 9 x 13 inch pan. Melt chocolate chips, marshmallows, and milk in double boiler. Add vanilla and cool. Fold in thawed whipped topping. Put 1/2 gallon ice cream over cooled cake layer, then spread chocolate mixture over top. Freeze.
Meringue: Beat 6 egg whites until foamy; add cream of tartar. Slowly add sugar until stiff peaks form. When dessert is completely frozen, spread meringue on top. Bake at 450 degrees for 3 minutes or until light brown. Cover completely and freeze until served. Allow to soften 10-15 minutes before serving.
