Wash the fish thoroughly, soak 1/2 an hour in cold water, skin side up; then cover with boiling water and let stand 5 minutes. Drain carefully, then remove the skin and bone. Put the flaked fish into a buttered serving dish and pour over it white sauce equal in quantity to that of the fish; cover with buttered crumbs and bake in a hot oven long enough to brown the crumbs.
