Brown Sauce

A small, thick roux-based sauce in the plainest terms — the whole thing hinges on how far you take the butter and flour before the liquid goes in.

• Browning is the recipeButter browned first, then flour cooked in it until nut-coloured, is what distinguishes this from a white sauce made of identical ingredients. Work over medium-low heat and stir constantly; milk solids in butter scorch quickly, and a burnt roux tastes acrid rather than deep.
• Clarified butter helpsBecause the butter is browned before the flour is added, the milk solids are already at the edge of burning. Using clarified butter or ghee gives you a much wider margin, though you lose a little of the browned flavour.
• Proportions are heavyThree tablespoons butter and four of flour to one cup of liquid is roughly double the thickening of a standard modern medium sauce. Expect something closer to a paste for masking or binding vegetables; thin with additional stock or milk if you want a pourable sauce.
• Milk or brown stockWith milk you get a browned-butter cream sauce; with brown stock, something meatier and darker. Brown stock here means beef or veal bones browned before simmering — a good unsalted beef stock is the nearest shop-bought equivalent.
• Adding the liquidAdd it a little at a time, as directed, and work each addition smooth before the next. Warm liquid incorporates more easily than cold, and browned flour has less thickening power than raw, so the sauce will look thinner than you expect until it has boiled.
• The five-minute boilThis is not padding — it cooks out the raw-flour taste and lets the starch reach full thickness. Keep stirring, because a roux this dense catches on the pan bottom in under a minute if left alone.
• SaltA full teaspoon of salt to one cup of liquid is a lot by current standards, and far too much if you use a salted commercial stock. Start with a quarter teaspoon and season at the end.
• YieldAbout one cup, which will sauce vegetables for roughly four depending on how thickly you use it.