This is a wonderful, delicate scallop dish - Coquille St. Jacques. It is made using multiple techniques of first creating a stock, a fish fumet, used for the court bouillon in which the scallops and mushrooms are poached. It is no minor task to then separate egg yolks from the whites, tempering the yolks into the liquid to create an exquisite sauce similar to a warm, savory sabayon. The coquille and mushrooms are then gently folded back into the sauce, spooned into scallop shells, and finished off under the broiler with a handful of grated gruyeres to provide the desired textural contrast.