Annie Bell's All-in-one Shrewsbury Lamb

Preheat the oven to 240C/220C fan/gas 9 (or its highest setting). Have ready the lamb joint, a large roasting dish or ovenproof frying pan and a large lidded casserole.
Peel the garlic and cut each clove into 4 slivers.

Make incisions all over the top of the lamb 1cm-2cm deep, slip a sliver of garlic into each one and season all over.

Heat the roasting dish over a high heat and colour the top and then the base of the joint, then pop it into the oven for 15 minutes (tuck in the knuckle if you have it and there’s room). Remove from the oven and turn down the temperature to 200C/180C fan/gas 6.

Meanwhile, peel, halve and finely slice the onion. In the large casserole, heat the oil over a medium heat and fry the onion for 7-10 minutes until golden, stirring frequently.

Stir in the mustard and then the redcurrant jelly, working it until smooth, then blend in the port followed by the stock. Place the lamb and knuckle, if present, in the casserole, with the rosemary sprigs on top. Bring the liquid to the boil, then cook uncovered in the oven for 30 minutes, by which time the juices should have reduced by about half, then cover and cook for another 15 minutes.

Transfer the joint to a warm plate, loosely cover with foil and leave to rest for 15-20 minutes. Discard the knuckle if included, skim the fat off the juices, stir in the lemon juice and taste for seasoning. Reheat and serve with the lamb.