400g pack diced mutton or lamb shoulder, finely choppped
2kg large potatoes, such as King Edwards, thinly sliced
300g carrots, sliced at an angle
3 tbsp plain flour
700ml lamb or beef stock, plus 450ml (optional)
2 tbsp Worcestershire sauce
steamed green beans and wilted spinach with nutmeg (optional), to serve
Heat oven to 190C/170C fan/gas 5. Cut small pockets into the skin and flesh of the lamb by piercing it with the point of a sharp knife. Stuff each pocket with a slice of garlic, using 3-4 of the cloves, and a few leaves of rosemary. Stuff some more inside the lamb, with some thyme, where the bone has come from. Put in a roasting tin, season well and cover with foil.
Melt half the butter in a large frying pan. Fry the onions, stirring frequently, until softened and golden. Tip into a second large roasting tin. Cook the chopped mutton or lamb in the pan until brown. Add to the onions in the tin, and toss with the potatoes, carrots, remaining garlic and herbs (chopped), 2 tbsp of the flour and some seasoning.
Pour the stock into the frying pan, then add the Worcestershire sauce and the remaining butter. When melted and boiling, pour over the potatoes, cover with foil and bake with the lamb for 1 hr.
Uncover both the lamb and the hotpot, and cook for 45 mins more until the potatoes are golden and cooked all the way through. Allow the lamb to rest for 15 mins before carving. Leave the potatoes in the oven (covered if starting to brown too much) until ready to serve.
Drain the fat from the lamb’s roasting tin, reserving the juices. Put the tin on the heat and stir in the remaining flour. Pour in 450ml boiling water or stock and stir until thickened to a gravy. Cut the hotpot into 8 and lift onto warmed plates. Carve the lamb into thick slices and place on top, then spoon round a little gravy. Serve with the green beans and spinach - add a little grated nutmeg to the spinach, if you like.