Method

1. Preheat the oven to fan 160C/ conventional 180C/gas 4. Weigh the ham and calculate the cooking time at 25 minutes per 500g. Scatter the onion, ginger, thyme and cloves over the base of a large, deep roasting tin. Put the soaked ham on top and add water to 3-5cm deep. Cover the whole ham and tin with two or three layers of foil (making a tent over the ham to allow the steam to circulate), sealing the foil around the edges of the tin. Bake for 1½ hours, then reduce the oven to fan 140C/conventional 160C/gas 3 for the remaining 2 hours 40 minutes of the cooking time. When the ham is cooked, remove it from the oven. Leave to rest for 30 minutes.

2. Now make the glaze. Put the sugar and 100ml/3½?2fl oz water in a medium pan. Heat gently until the sugar melts, add the fresh ginger and simmer for 3-4 minutes. Add the kumquats and cook for a few more minutes, just until they soften. Scoop out and reserve the kumquats, discard the ginger and add the stem ginger strips. Bring to the boil, then turn down the heat and let the mixture bubble for 3-5 minutes until thick and reduced by just under half. Remove from the heat and set aside.

3. Line a clean roasting tin with foil and oil it. Unwrap the ham and put it in the foil-lined tin. Cut off the skin, leaving a layer of fat all over. Using a sharp knife, score the fat into a diamond criss-cross pattern. Turn up the oven to fan 200C/conventional 220C/gas 7.

4. Rub ground ginger over ham, then brush over all but a couple of spoonfuls of the glaze, distributing stem ginger strips. Scatter over kumquat slices, studding cloves through some to secure. Drizzle over remaining glaze. Roast for another 20 minutes or until golden and sticky and kumquats start to colour. Serve garnished with halved kumquats and sprigs of bay leaves. If serving hot, allow to rest for 15-20 minutes before carving.