Remove the top layer of cake from the rest of the cake, and remove the cake topper or anything else that isn't edible.
Refrigerate the cake overnight in order to firm up the icing.
Wrap the cake in plastic wrap and make sure the cake is thoroughly covered.
Place the wrapped cake pieces in freezer bags. If you want to be extra safe, you may want to double bag the pieces.
Use a vacuum sealer or even a straw to suck out the excess air from the bags. Any oxygen left in the bag will start to suck moisture from your cake.
Place the bags of cake into the large plastic container.
Place the container in the freezer, and do not disturb for one year.
