Allemande Sauce or Thickened Velouté

Sauce allemande (velouté thickened with egg yolks and cream) teaches liaison, the egg-yolk-and-cream thickening that gives a sauce body without heaviness. Know one thing before you touch the pan: the butter enters only at the last moment, completely off the fire. Once it is in, the sauce must never cross 140°F, or its ivory gloss can turn oily and break.

The original formula assumed a saucier on staff, a pot of white stock always ready, a thick sauté pan over an open fire, and enough service to justify stirring the sauce until cold. Your equivalents are a wide, heavy-bottomed saucepan, a flat-edged whisk, a fine strainer, and an ice bath. The exact ratios remain, made as a finite two-quart foundation batch for one cook. Cooling and reheating are service scaffolding, so you may omit that loop when serving at once; the reduction, liaison, straining, and last-minute buttering are the dish and must stay.

When it is right, the allemande falls from a spoon in a smooth ivory ribbon and leaves a clean track when you draw a finger through its coating. Give your attention to the bottom of the pan during reduction, then to the temperature during the final buttering. If the emulsion turns, don't pour it away. Ça se rattrape.