450g / 1lb Maris Piper (or other floury) potatoes, sliced
½onion, thinly sliced
1carrot, thinly sliced
sprig of rosemary, chopped
For the Roast Shallots
50g / 2ozbutter
45g / 1½ozsugar
The day before: put the lentils to soak in cold water overnight.
The next day: start making the Rosemary Juice (see overleaf): preheat the oven to 200°C/400°F/gas 6. Chop up the lamb bones as small as possible and roast them in the oven until golden, about 1 hour (make sure you don’t allow them to burn, or scrape off any burnt bits if you do; otherwise the stock will be bitter).
Chop the onion, carrots, celery and garlic. Place them in a heavy-based pan and brown in a little oil. Add the chopped tomatoes and cook till most of the liquid has evaporated. Add the wine and reduce down by half. Add the thyme and most of the rosemary. Place the browned bones in the pan, cover with water and bring to the boil. Skim off any fat and scum, reduce the heat and simmer for about 4 hours. Pass the stock through a sieve into a clean pan, return to the heat and bring to a simmer again, continually skimming. Taste the stock now fairly regularly as it can get too strong, or sometimes over-salty due to the natural salts in meat. When it has a good strong flavour, pass it through a fine sieve. Check the consistency; if it is too thin (it should have a thin pouring consistency) thicken it with a small amount of arrowroot.
While the lamb stock is reducing, start the Hot-pot Potatoes: preheat the oven again to 200°C/400°F/gas 6. Butter an ovenproof dish about 20cm / 8inch round and 10cm / 4inch deep and season it with salt and pepper. In separate bowls, mix the potatoes, onion and carrot with some of melted butter and season well with salt, white pepper and rosemary. Layer the larger and longer potato slices neatly in the bottom and around the side of the dish, overlapping them well. Fill with the remaining vegetables, cover with a lid or foil and bake until cooked and golden brown, about 1 hour. Allow the hot-pot potato cake to cool for 30 minutes before turning it out. (This can be assisted by warming up the bottom of the dish for a few seconds.)
At the same time, prepare the Braised Lentils: drain the lentils and put them, together with all their other ingredients, in a large pan and bring to a simmer. Cook until the lentils are tender, about 30 minutes depending on type. (You may have to keep topping up the pan with boiling water to prevent the contents drying out.)
About 25 minutes before you want to serve, prepare the shallots (see overleaf): preheat the oven again to 200°C/400°F/gas 6. Melt the butter and sugar in an ovenproof pan until golden brown. Add the shallots, and toss to colour them well, then cover with water and braise in the oven until reduced and shining, about 15 minutes. Season to taste with salt and pepper.
While the shallots are braising, cook the peas and carrots in boiling salted water until just tender. Blanch the cabbage whole for 2 minutes only. Refresh them all immediately in iced water and drain. Shred the cabbage.
Cook the lamb: season the rack and roast in the oven with the shallots for 8-10 minutes, until done to taste. Remove from the oven and allow to rest briefly, covered with foil to keep it warm.
While the lamb is roasting, cut the hot-pot potato cake into wedges with a sharp knife and reheat in the oven with the lamb.
To serve: finish the rosemary juice, pick the remaining rosemary off the stalk, chop and add to the sauce. Reheat if necessary. Reheat the vegetables in a pan with a knob of butter and 2-3tablespoons of water. Season to taste. Carve the lamb into individual chops.
Arrange a pile of spring vegetables just to one side of the centre of each plate and arrange two lamb chops, bones crossing, resting on the pile of vegetables. Put a wedge of hot-pot potatoes in the space between the bones and a pile of braised lentils on the other side of the plate, topped with some roast shallots. Spoon some rosemary juice around the plate.