Cakes with frostings or fillings containing dairy products should be refrigerated.
If a cake has a fluffy cooked frosting, insert a knife handle under an edge of the cake cover so it isn't airtight. The frosting can be totally absorbed by the cake when stored in an airtight container. If you don't have a cake cover, cakes with creamy frostings also can be covered lightly with foil, plastic wrap, or wax paper. To keep the frosting from sticking to the protective covering, insert several toothpicks halfway into the cake around the edges and in the center to support the covering.
For unfrosted butter cakes, cool completely, wrap in heavy-duty foil, and freeze. Foam cakes may be frozen in the pan to prevent crushing. Cover tightly and freeze. Unfrosted cakes may be stored in the freezer up to six months.
Freeze frosted cakes in a tightly covered plastic container. Or, place cake in freezer until frosting is frozen, and then wrap tightly in plastic wrap or foil and freeze up to three months.
Place layer cakes in a box or cake container to prevent crushing, and then wrap the box in foil or plastic wrap before freezing.
Thaw unfrosted cakes covered and frosted cakes loosely covered for two to three hours at room temperature.