Decorticate the flesh of the scampi and keep the tail and brown them in a pan with a little butter or goose or duck fat for about 8 minutes on slow heat. Salt and pepper lightly. Prepare a french dressing by mixing the raspberry vinagre, the walnut oil, a few leaves of thyme with lemon juice, salt and pepper. Just as you serve it, put the slices of foie gras on the individual plates and add on the side the warm tails of scampi sprinkled with a few small spoonfuls of raspberry vinagre. Decorate with a few sprigs of thyme soaked in lemon juice and the chevril.