Heat the oven to 220C. Cut the lamb rack in half (ie, two pieces of four ribs each), then rub with a teaspoon of flaked salt and lots of pepper. Heat a tablespoon of olive oil in a large frying pan on a high flame and, once hot, lay in the lamb skin side down and fry for five minutes, or until the fat is golden brown, then transfer to a large bowl.
Blitz all the marinade ingredients in a food processor with a teaspoon of flaked salt and plenty of pepper. Coat the lamb in the marinade and leave at room temperature for an hour, or refrigerate overnight (in which case, leave it to come back to room temperature before cooking).
Put all the ingredients for the vegetables in a large oven tray lined with greaseproof paper, then add 250ml water, a teaspoon of flaked salt and a generous grind of pepper, and toss. Roast for half an hour, until the vegetables are lightly coloured.
Lay the lamb fat side up on top of the vegetables, roast for 15 minutes, then transfer the lamb to a plate, cover tightly with foil and leave to rest. Turn the grill to its highest setting and put an oven rack in the middle of the oven. Toss the bread with two tablespoons of oil, then stir into the veg. Arrange the bread pieces so they are on top of the vegetables, then grill for six minutes, until crisp and golden.
While the bread is grilling, mix all the yoghurt sauce ingredients with a generous pinch of salt.
Transfer the vegetables and bread to a shallow platter and gently fold in the herbs. Cut the lamb into eight cutlets, sprinkle generously with flaked salt, then tuck under and in between the vegetables. Drizzle over the sauce and the last tablespoon of oil, and serve.
