Crayfish Mariniere

Remove the small claws from a dozen or two of crayfish, place them in a stewpan,
and boil with wine until done. Drain off the liquor, allow it to settle, and then
pass it through a fine sieve to clarify it. Take an onion, chop it up finely, and fry
gently so that it does not color at all. Pour on a little of the crayfish liquor and also
a little wine, and boil for three minutes. Next put in a lump of butter worked into
some breadcrumbs and finely-chopped parsley to thicken it, and finally add a little
cayenne and the juice of a lemon. Place the crayfish on a dish and pour the sauce
over.