Also called béchamel or by its Italian name, balsamella, this basic French white sauce is made by stirring milk into a butter-flour roux. The thickness of the sauce depends on the proportion of flour and butter to milk. The proportions for a thin sauce would be 1 tablespoon each of butter and flour per 1 cup of milk; a medium sauce would use 2 tablespoons each of butter and flour; a thick sauce, 3 tablespoons each. Béchamel is one of the four "mother sauces." It was named after its inventor, Louis XIV's steward Louis de Béchamel.
From The Food Lover's Companion, Fourth edition by Sharon Tyler Herbst and Ron Herbst. Copyright © 2007, 2001, 1995, 1990 by Barron's Educational Series, Inc.