Thoroughly cleanse four heads of white celery and slice them very thin; put this into a stewpan with nutmeg, pepper, and salt, and four ounces of butter and an onion sliced; put the lid on the stewpan and set it over a slow fire to stew very gently until the celery is dissolved, without acquiring any colour.
Then add four ounces of flour and a pint of milk; stir again over the fire until the sauce has boiled twenty minutes, and then, having rubbed it through a sieve or tammy, put it into a small stewpan; to be used for boiled poultry or game.