As described above, you can make the carrot cake layers even weeks ahead of time by wrapping them tightly and freezing them. Defrost in the refrigerator before frosting and serving.u003cbr/u003eu003cbr/u003eThe cake is moist enough, in fact, that you can even store it at room temperature, wrapped tightly in plastic wrap, up to 1 whole day in advance. Don't refrigerate it, though, as the refrigerator tends to dry out baked goods.u003cbr/u003eu003cbr/u003eThe frosting can also be made in advance and stored in the refrigerator for a few days. It will be solid, though, once fully chilled, so you'll need to let it warm up for about an hour, and then mix it again with your mixer until you reach the proper consistency for spreading or piping it.