Place cake layers, top side up in two clean 8 or 9 inch round cake pans. Prick each cake with a utility fork at 1/2 inch intervals.
Dissolve gelatin in boiling water. Carefully spoon dissolved gelatin over cake layers. Chill cakes for 3 to 4 hours.
Dip one cake pan in warm water for 10 seconds, then unmold onto a serving plate. Top with about 1 cup of the whipped topping. Dip the other cake pan in warm water for 10 seconds and unmold second cake layer, placing carefully on top of the first cake layer. Frost top and sides with the remaining whipped topping. Chill.