This gammon is simply simmered in ginger ale and, although you need to strip off the rind to glaze it, the glaze is straightforward. And it is a very efficient way of cooking — depending on how many you have in your household to feed, you should be able to eke this out for several meals.  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. And please read the Additional Information section at the end of the recipe before proceeding. For US cup measures, use the toggle at the top of the ingredients list.