Béchamel is white roux combined with hot milk — one of Escoffier's five mother sauces and the foundation of gratin preparations, sauce Mornay, croque monsieur, and moussaka. It is simultaneously the most common and the most badly made sauce in the home kitchen, almost always because the roux was undercooked (raw flour taste) or the milk was added incorrectly (lumps).
- **The roux must be cooked long enough.** A minimum 2 minutes after the foam subsides removes the raw flour taste that makes most home-made béchamel objectionable. - **Hot milk into hot roux.** Add the first third of the milk vigorously — this is where lumps either form or don't. Whisk rapidly during the first incorporation. - **Nutmeg.** Freshly grated nutmeg is the classic seasoning — add the smallest amount that can be tasted but not identified. "You'd miss it if it were gone" is the correct level. - **Nappe consistency.** The finished béchamel should coat the back of a spoon and hold a finger-drawn line clean for 8 seconds. Decisive moment: The nappe test — not the clock. Different milk temperatures, different flour types, and different pan sizes produce different results at the "correct" time. Taste and assess consistency, then decide.
Jacques Pépin's Complete Techniques