LEEKS
Cut leeks into three-inch lengths, using the tender green part as well as the white; wash the pieces thoroughly in cold running water, then put them in a small saucepan and cover them with boiling salted water, and let them boil for twenty minutes.
Make a sauce by melting 1 tablespoon of butter and thickening it with 1 tablespoon of flour, and then adding, 1 tablespoon at a time, enough of the water the leeks were cooked in (about 1 cup) to make the sauce of the right consistency; season with pepper and salt, drain the leeks, and serve the sauce over them.