How to save the top tier of your wedding cake.
Most couples freeze the top tier of the wedding cake with the intention of sharing it on their first wedding anniversary; it serves as a pleasant reminder of their very special day.
How To Save:
To Freeze: Place top tier of cake in freezer unwrapped for 5-6 hours so the icing and any decorations can set. Then, cover with plastic wrap, then foil, and then double-bag (or even triple-bag) it in large freezer bags. Either use a vacuum sealer or suck out all the air from the bags using a straw to get a vacuum-tight seal (extra air will leech moisture from your cake). Place the wrapped cake in a bakery box to protect it from being damaged by other goods in the freezer.
(Note: If your cake has a custard filling, freezing it is not recommended because the filling could separate.)
Remove from freezer at least 12 hours before serving. Let thaw in its wrappers so condensation forms on them and not the cake.