The answer to this question varies depending on whether you are making a traditional Christmas cake or a last-minute Christmas cake. Traditional Christmas cakes should be made at least 4 weeks in advance. The cake needs time for the flavours to mature and it must be fed alcohol at least 3 times over the space of a few weeks to help ramp up the richness and those festive flavours. If that all seems like too much hassle, then consider my easy marzipan Christmas cake recipe. It is a much simpler affair. There is no need for maturing or feeding. Instead, it can and should be eaten straight away, so make it on Christmas Eve. It will last easily for at least a week.