ONE OF THE MOST sublime preparations to come out of the French kitchen is a well-made fish mousseline. Essentially a fish purée bound by egg whites and enriched by heavy cream, it can be poached, steamed, or baked. It can be used as a stuffing, as in
Mousseline-Stuffed Trout with Two Sauces; or baked in a mold and served with a sauce, as for
Fish Mousseline with a Hidden Scallop or