Sauce Suprême

Sauce suprême is a nineteenth-century refinement of the white velouté, codified in the grande cuisine of Carême's and Escoffier's era. The word suprême in classical French cookery means both the boneless breast-and-wing fillet of a bird and, by extension, a particularly fine, smooth sauce; the two meet on the plate of suprême de volaille sauce suprême. Escoffier's Le Guide Culinaire gives it as a chicken velouté reduced with white stock, mushroom cooking liquor and cream, strained, and mounted with the best butter. It belongs to the same family as the older sauce allemande, which is bound with egg yolk instead, and the two were often distinguished only by their finishing.

Pale and satiny, it pools cleanly around the chicken and coats a spoon in an even sheet. The flavour is delicate and unmistakably of poultry, deepened by the mushroom liquor and rounded by cream, with the lemon and butter keeping it bright rather than heavy. It should taste rich but never floury or claggy; a sauce that breaks into a starchy film or tastes of raw flour means the velouté was under-cooked or the reduction rushed.

The base is a blond roux — flour cooked in butter just to the point where its raw taste is gone but it has barely coloured — whisked with chicken stock into a velouté, where the starch granules swell and gelatinise to thicken the liquid. Long, gentle simmering and skimming clarify it and cook out any floury edge. Reducing it with cream concentrates flavour and, because cream's own fat and protein add body, lets the sauce thicken further without more flour. The final lemon does two jobs: it brightens the flavour and its acid keeps the sauce from tasting flat, while the cold butter swirled in at the end emulsifies into the warm sauce for gloss and a smooth finish.