Instructions

1. Preheat the oven to 160°C.
2. Poke holes all over the meat with a knife and push in the rosemary leaves, then place it in a roasting dish. Drizzle with the oil, season with salt and pepper then scatter the remaining rosemary leaves on top. Pour in the wine.
3. Cover the dish with foil and bake for 3 hours.
4. Break open the garlic but don't peel the cloves. Push them down slightly with a knife and scatter them around the lamb. Cover the dish again and bake for 30 minutes.
5. Take the dish out of the oven, pour the sauce into a jar. Rub the meat is thoroughly with the chilli jam and return it the roasting pan then to the oven and bake for another 30-40 minutes. It's ready when the glaze is golden brown and sticky.
6. Let it rest, covered, for 15 minutes before serving.
7. Meanwhile, skim the excess fat off the cooking juices in the oven pan, sprinkle with a little cornflour and reduce it to a thick gravy on the hob.
8. Carve the lamb and pour over the gravy.