For the lamb jus: preheat the oven to 180C/gas 4. Roast the lamb carcasses on a roasting tray in the oven until lightly browned.
Combine the olive oil, onions, leeks, carrots and garlic in a pan and cook until softened, Add the thyme, cumin seeds and cinnamon and cook for a further 5 minutes.
Stir in the tomatoes and tomato purée and simmer for 10 minutes.
Place the roasted bones into a large stockpot, add the cooked vegetables, water, veal glace and chicken stock. Bring to the boil, reduce to a simmer and cook for 30 minutes.
Strain the mixture through a colander into a clean pan. Simmer again until reduced by half.
Pass the mixture through a piece of muslin tied with string into another clean pan. Set aside, keeping the jus warm and discarding the vegetables.
For the herb crust: place the breadcrumbs, parsley and garlic into a food processor and blend to a fine crumb.
Add the olive oil, a pinch each of salt and white pepper, and the Dijon mustard. Blend until the mixture comes together as a paste. Remove and place on a tray.
For the lamb: increase the temperature of the oven to 200C/gas 6 and season the lamb with salt and pepper.
. Heat the vegetable oil and butter in a small roasting tray and brown the lamb on all sides on top of the stove. Place the lamb fat-side down into the tray and transfer to the oven.
. Roast for 5 minutes, then turn the lamb over and roast for a further 4 minutes. If you prefer your meat more well done, you can add an extra 3-5 minutes cooking time. Remove from the tray and leave to rest, in a warm place, for 15 minutes. Keep the oven on.
. Brush the lamb with Dijon mustard and then press it into the herb crust. Place on a roasting tray ready to reheat.
. For the minted new potatoes and peas: scrub the new potatoes well with a brush and wash under cold running water.
. Cover the potatoes with the water in a pan, add the powdered chicken stock, salt, thyme, mint, bay leaves and garlic and bring to the boil.
. Reduce the potatoes to a simmer and, once they are tender, drain and put them back into the pan. Stir in the chopped mint leaves and butter and season with salt and pepper.
. Cook the peas in a pan of boiling salted water until tender. Drain.
. Place the lamb back into the oven to reheat 5 minutes before serving, then remove the lamb from the oven and carve it into cutlets.
. To serve, place 2-3 cutlets on each serving plate, scatter the warm buttery minted potatoes and peas around and serve with the lamb jus.
