Purée d’Oignons, dite Soubise

Purée d’Oignons, dite Soubise (silken onion purée) teaches the difference between depth and darkness. The onions must grow sweeter and fuller in butter without taking color. Brown them and you have made a good onion sauce, but not Soubise. The one true thing before you touch the pan is this: gentle stewing, not caramelizing, makes the flavor.

The source formula, Soubise Sauce (No. 104), assumed a saucier tending the pan, thick Béchamel waiting at the sauce station, and a broad tammy through which a brigade could pass the onions quickly. At home, one wide pan replaces the station, prepared Béchamel supplies the foundation, and a fine-mesh sieve does the tammy’s work. I have changed the equipment and reduced the service routine to one measured, make-ahead batch. I have not changed the sequence or the onion-to-Béchamel proportion. The brigade was scaffolding. The slow butter stewing is the dish.

When it is right, Soubise is ivory-colored, softly sweet, and glossy enough to hold the trail of a spoon before settling. It tastes first of onion made round and deep, then of cream and butter, never of browned sugar. One cook, one stove, one evening. Watch the onions during that pale butter stew, because this is the step that decides the sauce.