Buttercream frosting provides a barrier to keep a cake from drying out, but most cakes last only about a week left on the counter or in the fridge. Freeze a cake to maintain its freshness for as long as six months. This is a good option if you want to have a cake on hand for when you might need it, or if you want to store leftover cake. A few steps ensure that your frosted cake emerges from the freezer as delicious and beautiful as when it went in.
Place a piece of aluminum foil against the exposed part of the cake if you're freezing a cake that has been cut. Cut the foil to size with a pair of kitchen scissors and press it up against the exposed cake. If it doesn't stick on its own, swipe a bit of buttercream frosting on the back side of the foil to act as a glue to hold it in place.
Place the frosted cake on a tray or in a cake storage container, and set it in the freezer unwrapped for about four hours, or until frozen solid. Clear out enough room to set the cake in the freezer without it touching anything else. Clean the freezer to remove an lingering odors, if needed, because the unwrapped cake can absorb them.
Take the frozen cake out of the freezer and wrap it in several layers of clear plastic wrap. Wrap the plastic tightly around the cake but don't press down hard on the frozen frosting and decorations, which may be crushed by too much pressure. If necessary, wrap the cake in 10 loose layers of plastic rather than in two tight layers. If the frosting is spread smooth, lay the plastic wrap carefully without any wrinkles to achieve even smoother frosting.
Wrap aluminum foil on top of the plastic wrap. Use multiple pieces, if needed, to ensure that all sides are sealed well.
Label the cake with the storage date and the expiration date, which should be four to six months from the storage date. Write directly on the aluminum foil with a permanent marker, or write the information on a piece of freezer tape and secure it to the foil.
In a cake box or cake storage container, freeze the cake inside and wrap the entire container in plastic and foil. This is especially useful for layer cakes and cakes with 3-D decorations, because it prevents the cake from being crushed.
Cakes taste best when consumed within six months of the storage date, but that doesn't necessarily mean they go bad after six months. For example, it's common tradition for a married couple to freeze the top tier of the wedding cake to serve on the first wedding anniversary.
To defrost a frozen cake with buttercream frosting, remove the aluminum foil and plastic wrapping and set it in the refrigerator overnight. Set it out at room temperature for an hour or two before serving.