Slow-roast shoulder of lamb

1. Preheat the oven to 170˚C, gas mark 3. Put the onion, 2 rosemary sprigs and 4 garlic cloves in the bottom of a roasting tin. Peel the remaining garlic and strip the leaves from the remaining rosemary. Put in a pestle and mortar with the lemon zest and olive oil. Crush gently until you have a very coarse paste.

2. Place the lamb in the roasting tin so it sits on top of the onion, garlic and rosemary and cut several small slashes on the top of the joint. Rub the garlic and rosemary paste all over the lamb and into the cuts; season. Wrap the roasting tin tightly in a double layer of foil and roast for 3 hours 30 minutes. Uncover the tin and discard the foil. Roast the lamb for another 30 minutes to allow the skin to crisp up.

3. Remove the lamb from the roasting tin and place on a platter; lightly cover with foil and allow to rest. Discard the onion, garlic and rosemary from the tin and spoon out and discard the fat (there might be quite a lot).

4. Put the roasting tin over a medium heat on the hob, add the stock and scrape up any caramelised bits with a wooden spoon. When the juices come to the boil, stir in the redcurrant jelly. Boil until the juices are syrupy and the redcurrant jelly is dissolved. Add the lemon juice, then transfer to a jug.

5. The lamb should be tender enough to pull apart with a fork. Place on the table with the gravy, potatoes and braised peas, and let people serve themselves.