Lamb shoulder with garlic potatoes and redcurrant glaze

Heat the oven to 200C/fan 180C/gas 6. Put the lamb in a large roasting tin and season well. Cook in the oven for 40 minutes uncovered then turn the oven down to 160C/fan 140C/gas 3, cover with foil, and keep cooking for another 3 hours.

While the lamb cooks, make the glaze. Put all the ingredients in a pan and simmer for 3-4 minutes or until lightly syrupy.

Drop the potatoes into a large pan of boiling salted water, bring back to the boil and cook for 8-10 minutes or until just tender. Drain well.

Remove the lamb from the oven then turn the oven up to 190C/fan 170C/gas 5. Take the lamb from the tin and strain the fat into a jug (there should be plenty of it).

Put 5 tbsp of the lamb fat in a clean shallow roasting tray that will fit all the potatoes, then tip them in along with the garlic and rosemary. Toss them around in the fat and season.

Return the lamb to its original tray and brush it all over with ¹/2 the glaze.

Put the potatoes in the oven on the top shelf with the lamb beneath. Cook for 30-40 minutes, brushing the lamb with more glaze, until it’s nicely browned and the potatoes are golden. Take the lamb out to rest after 30 minutes and, if the potatoes need more browning, turn up the oven a little and keep cooking for 10-15 minutes or until golden and crisp.

To make the salad, whisk the shallots, vinegar and mustard, then gradually whisk in the olive oil with 1 tbsp water. Season, then toss with the peas and watercress. Serve with the lamb and potatoes.