Instructions

1. Place the garlic, anchovies, leaves from 6 of the rosemary sprigs, olive oil and black pepper in a mini processor and whiz to combine. You can do this with a mortar and pestle if you prefer – mix the garlic and anchovies first, then chop the rosemary leaves finely and add them in along with the olive oil and pepper.
2. Place the lamb in a large non-metallic dish and rub the mixture all over it. Cover with clingfilm and set aside for 2 hours to allow the flavours to combine. Overnight in the fridge is even better.
3. Preheat the oven to Gas Mark 7, 220°C (450°F). If the lamb has been chilled overnight, bring it back to room temperature. Then place it skin side up, in a large roasting tin. Scatter the reserved rosemary sprigs over the top. Roast the lamb for 10 minutes, then turn reduce the temperature to Gas Mark 4, 180°C (350°F) and continue to roast for another 35 minutes. The lamb will be cooked medium at this stage. Remove from the oven, transfer to a carving board, cover loosely with foil and allow to rest for 10 minutes before carving.
4. Add a dash of wine or water to the juices left in the pan and boil.
5. Serve with the sliced lamb, roast or gratin potatoes and green beans tossed with toasted pinenuts.