Cover cake layers with plastic wrap and freeze for 8-10 hours or until ice cream is solid to touch.
Remove cake layers from freezer and discard plastic wrap. Using a paring knife, run blade around edge of one of the cake layers to separate it from pan.
Invert cake layer onto a plate, then turn it over onto another cake plate so that the ice cream layer is facing up.
Invert 2nd cake layer onto the 1st layer, again by running a knife around edges of pan to release cake.
The two ice cream layers should now be assembled one on top of the other. Press down gently so that the ice cream layers sort of seal together. Using a cake spatula, smooth sides of cake.
Return cake to freezer while you prepare frosting.