How long can you keep Nigella's Chocolate Christmas Cake once once you have cut into it?
Christmas cakes and rich fruit cakes tend to keep quite well once they have been cut into, unlike sponge cakes. We would suggest that Nigella's Chocolate Fruit Cake (from Christmas and now on the Nigella website) the cake is kept in an airtight container or cake tin in a cool, dry place, and it should keep for 2 weeks to 1 month.
You could also freeze individual wedges for up to 3 months. Wrap each wedge tightly in clingfilm and then pack the wedges into an airtight container or a large plastic freezer bag before freezing. Slices should take 1-2 hours to thaw at room temperature.