Since the cake is made with oil and contains plenty of moisture, you can bake the layers up to a day or two before you need them (or up to three months in advance if you want to freeze them). For storage at room temperature or in the fridge, cool completely and then wrap each layer gently but thoroughly in plastic wrap. For freezer storage, once cool, wrap in plastic wrap, followed by foil, followed by a zip-top freezer bag. I like to assemble and frost the cake on the day of serving. Assembled cake, and any leftovers, can be stored in an airtight container (like this one) in the fridge for a week.