Slow-cooked Moorish lamb with buttermilk dressing

Method

1. Rub the meat with the olive oil and season well with salt and pepper. Rub the paprika, crushed coriander seeds and cumin all over the lamb. Lay out a large double layer of foil, put the lamb on top and nestle the garlic bulb pieces underneath. Drizzle over the vinegar, then fold the foil around the joint to completely seal the lamb. Leave the wrapped meat to marinate in the fridge for at least 5 hours or overnight.
2. Heat the oven to 140°C/120°C fan/ gas 1. Put the foil-wrapped lamb in a shallow roasting tray, then open up the foil around the meat, so the steam from the oven can get to the meat. Half fill a large deep roasting tray with water and set a rack on top so the rack is out of the water. Put the tray with the lamb on top of the rack, then cook in the oven for 4½-5 hours until tender, turning the meat every couple of hours and topping up the water if it evaporates too much.
3. When the meat can be pulled apart with a spoon it’s ready for the barbecue. Take the slow-cooked lamb out of the foil and put it onto the hot barbecue grill for 20-30 minutes so the outside of the meat browns and takes on some of the smoky flavour (be careful as the dripping fatty juices from the lamb may make the coals flare up). If you have a barbecue with a hood, you can cook it with the lid down to trap the smoke.
4. For the dressing, whisk together the buttermilk, vinegar and garlic and season well. Rest the lamb in a warm spot for 20-30 minutes, then serve with the buttermilk dressing.