Take a sharp knife and a large jug filled with hot water. Dip the knife into the hot water then cut the foie gras at a slight angle into 1½-2 cm thick slices. Put them into the fridge until required.
If the ceps look very sandy or dirty, scrape them with a small knife and wash them briefly in a bowl of water, then dry them on a cloth.
Slice them through, not too thinly, then hea