Place in a casserole, or shallow earthenware cooking vessel, a sole, fillets of turbot, brill, or almost any other white fish, and add twenty shelled mussels with a little of their liquor, and a few heads of small button mushrooms. When almost cooked drain off the sauce, arrange the mussels and mushrooms round the fish, strain the sauce and thicken it with the yolk of an egg. If there is not sufficient sauce add a little strong clear stock thickened with butter and flour. Replace the cover on the vessel, let it cook for two or three minutes longer, and serve very hot.

Another method is to strain off the sauce entirely and replace it with a brown sauce made by adding clear stock butter to a little melted butter thickened with flour.