Treacle-roast ham with spiced rum glaze

Method

1. If necessary, soak the gammon overnight in cold water (see Know-how). To cook, use a pan that can hold it comfortably and fill to halfway with cold water (see tip). Add 400ml of the black treacle or molasses and stir to dissolve. Add the gammon with the bay and spices. Top up with water to cover, then bring to a very gentle simmer and cook for around 2½-3 hours until the middle of the ham reaches 65°C when tested with a digital thermometer (see video in tips). Skim off any surface scum as the meat cooks.
2. Remove the ham and leave to cool until you can handle it, or leave to cool completely (see Make Ahead).
3. Preheat the oven to 200°C/fan 180°C/gas 6. Using a sharp knife, cut the skin off the ham, leaving as much fat as possible. Score the fat into a diamond pattern.
4. Mix the remaining 50ml treacle/molasses with the rum and mustard powder, then brush generously over the fat. Transfer the ham to a roasting tin double-lined with lightly oiled foil, then roast for about 20 minutes, basting with the glaze in the tin once or twice. When the ham is glossy and sticky, remove from the oven. Leave to rest for 30 minutes, then slice.