Preheat your oven to 180˚C. For the dauphinoise warm your milk and cream in a pan to infuse with the Black Truffle Sauce, garlic and thyme. Then cook the thinly sliced potatoes on the hob for 5 mins. Using a slotted spoon remove the potato and layer into a shallow ovenable dish. Cover the potatoes with the truffled cream and milk – remove the garlic cloves. Then sprinkle with grated cheese and bake for 35-40 mins.
For the lamb rub with oil and season with salt and pepper. Then sear the meat on all sides in a pan until brown. Add butter, garlic and thyme and cook for 5 mins. Transfer to a wire rack and roast in the oven for between 10-15mins for rare / medium. I cook until the internal temperature reaches 54˚C for medium rare.
Meanwhile in a small mixing bowl combine a crust for the lamb with breadcrumbs, chopped herbs and Black Truffle Sauce.
Rest and then cover the skin side of the rack with some truffle mustard. Spread your herby Black Truffle sauce onto the rack so it sticks and serve with your Truffle Dauphinoise and some wilted greens.