You can adapt this freely, depending on the number of people you want to feed at the first sitting (I did this for 11 adults and 6 children last year) and how many days you want to eke it out for afterwards. But what is important, given that this is probably the most labour-intensive time of year in the kitchen, is that this dispenses with any fiddly steps. The gammon is simply simmered in ginger ale and, although you need to strip off the rind to glaze it, the glaze is straightforward.
It won’t give that same crowning effect, but if you cannot get hold of ginger preserve, you could use ordinary orange marmalade and add a teaspoon of ground dried ginger or, indeed, grated fresh, as you heat it up.
Recipe posted by Nigella