If your gammon needs to be soaked to draw out some of the salt (ask your butcher), place in a clean bucket or a preserving pan and cover with cold water. Chill overnight, or for up to 3 days.
Heat oven to 160C/140C fan/gas 3. If the ham has been soaking, drain it well and place in a large, deep-sided roasting tin. Pour in the apple juice and top up with 400ml water. Add the spices, bay leaves and orange zest. Cover the ham tightly with a few large sheets of foil, scrunching it around the edges of the tin so no steam can escape, then bake for 5 hrs. Meanwhile, mix together the ingredients for the glaze in a saucepan, then bubble until reduced to a sticky glaze. Score the apples around their equator with a small, sharp knife.
Remove the ham from the oven and increase the temperature to 200C/180C fan/ gas 6. Carefully transfer the ham to a board – the easiest way to do this is to leave it to cool for 10 mins, then pop on clean washing- up gloves to lift it. Pour away the cooking liquid and discard the aromatics. Use a small, sharp knife to cut and peel away the rind, leaving a thin layer of fat attached to the meat. Line your roasting tin with a few sheets of foil and place the ham in the middle, fat-side up. Use a sharp knife to lightly score the fat in a criss-cross pattern. Return the ham to the oven and bake for 30 mins until the fat starts to crisp and caramelise.
If the glaze has become a little thick, splash in a drop of water to loosen it, then brush all over the ham. Place the whole apples in the tin too, and return to the oven for another 20-30 mins, basting the ham every now and then, until dark and sticky all over.
Before serving, mash the whole apples (discard the stalks, skin and pips) with a little of the sticky sauce from the roasting tin. We decorated our ham with star anise, sprayed with edible gold spray, and arranged bay leaves and orange peel around the board. Serve warm slices of the ham with the apple sauce, or cold in sandwiches. Will keep for up to 1 week in the fridge, or slice and store in the freezer for up to 2 months.