Sauce Ravigote

A preparation of classical French cookery whose name comes from the verb ravigoter, 'to revive' or 'to perk up' — a fair description of a sauce meant to wake up plain boiled and poached dishes. The classical canon records two ravigotes: a hot one, a velouté or white sauce sharpened with white wine, vinegar and a shallot-and-herb reduction finished with herb butter; and a cold one, the vinaigrette-based herb sauce with capers and onion described here. Escoffier's Le Guide Culinaire lists both. Over the twentieth century the cold vinaigrette version became the default, fixed above all by its classic pairing with tête de veau; no single inventor or date attaches to it.

Bracingly sharp and herbaceous, with the salty pop of capers, the bite of raw onion or shallot, and a green wash of parsley, chervil, tarragon and chives, all cut with mustard and vinegar. It is loose and spoonable, not thick, the oil carrying the herbs in suspension. Against the soft, fatty richness of boiled calf's head or a poached leek it lands clean and reviving — its whole job is contrast. Too much vinegar makes it aggressive; balanced, the mustard and oil round the edge while keeping the lift.

The base is a mustard vinaigrette — an emulsion in which mustard acts as the emulsifier, its mucilage and proteins helping the oil and vinegar hold together in a loose suspension that does not split on the plate. It is not cooked, so everything stays raw-sharp: the capers salty, the onion pungent, the herbs bright green and fragrant. The herbs are chopped, not blended, to keep their colour and texture; they are added at the end and the sauce is used soon after, because tarragon and chervil fade and the onion turns harsh if it sits too long. Acidity is the active principle, set against fatty, gelatinous foods to balance them.