Cover and store butter cakes for 2 to 3 days and foam cakes for 2 days at room temperature. Cakes with fillings or frosting that contain perishable ingredients (such as cream cheese, yogurt, whipping cream, sour cream and eggs) should be stored in the refrigerator.Unfrosted butter cakes and ones frosted with a simple buttercream frosting can be frozen. Place individual cake layers on a baking sheet and freeze. Once frozen, wrap in plastic wrap or place in resealable plastic freezer bags. Freeze unfrosted butter cakes for up to 4 months and frosted butter cakes for up to 4 months and frosted butter cakes for up to 2 months. Not all frostings are suitable for freezing. Freeze unfrosted foam cakes in their pan or in plastic bags for up to 2 months. Thaw cakes in the refrigerator.