Preheat oven to 220°C/450°F/Gas Mark 6. Brush lamb with 1 tablespoon olive oil, season with salt and pepper and leave to sit, covered, at room temperature. Put garlic, beetroot, bayleaf, rosemary, wine, vinegar, 3 tablespoons olive oil and some salt and pepper into a small ceramic roasting dish. Cover tightly and roast 45 minutes.
Place cous cous in a bowl and pour over water, stir well then mix in 2 tablespoons olive oil, herbs, 1 heaped teaspoon salt and some freshly ground black pepper. Leave covered in a warm place for 20 minutes then mix again – the grains should now be loose and plump. Remove foil from beetroot and roast a further 20 minutes.
Grill cutlets for 2-3 minutes on each side depending on thickness, but they will taste best pink. To serve, spoon some cous cous into the centre of a plate, place some roast beets and garlic on, then sit cutlets on top. Drizzle with roasting liquids. A simple green salad also goes well with this.