Bake cake mix in 2 layer pans as directed. (Freeze one layer for future use.)
Line 1 1/2 qt bowl with aluminum foil. Pack ice cream into bowl; freeze until firm. Cover baking sheet with aluminum foil. Place cake layer on baking sheet. Invert bowl with ice cream onto cake; remove bowl & foil. Freeze cake and ice cream until firm.
Just before serving, heat oven to 500 degrees F. Prepare frosting mix as directed on pkg. Working quickly, completely cover cake and ice cream with frosting, carefully sealing it to foil on sheet. Bake 3 to 5 min or until light brown. Trim foil to edge of frosting; transfer cake to serving plate. Serve immediately.