Beurre Blanc and Its Variations: The Mother Sauce of Butter

Beurre blanc is technically a broken emulsion that is not supposed to work but does. You reduce white wine, shallots and vinegar to almost nothing -- a concentrated, acidic, aromatic base -- then whisk in cold butter piece by piece until you have a velvety, pourable sauce. The acidity stabilizes the butter emulsion just enough to hold, but unlike hollandaise there are no eggs involved, so you are working entirely with the butter's own lecithin and water content. The result is lighter, brighter and more versatile than hollandaise, and it has an affinity with fish that makes it one of the great seafood sauces.

The fear of beurre blanc comes from its instability -- once made, it must be served within 20 minutes and cannot be reheated without breaking. This is entirely true, and the solution is simply to make it last. Begin the reduction well in advance; you can hold the reduced base for hours. Then finish with the butter in the final 5-8 minutes before plating. The butter must be cold when it goes in -- warm or room-temperature butter will not emulsify, it will just melt into a greasy pool. A small splash of cream added with the reduction (the Nantaise variation) provides an additional emulsifier and extends the holding time by 10 minutes.

Six seasonal variations worth knowing: in spring, add blanched tarragon and lemon zest for an asparagus sauce; in summer, infuse with basil and finish with a drop of Pastis for a Provencale fish sauce; in autumn, use red wine and shallot reduction instead of white for a red beurre blanc with game or duck; in winter, add a scraping of fresh truffle and a splash of Madeira for a luxurious accompaniment to beef tenderloin; year-round, a tablespoon of good grain mustard stirred in at the last moment makes a beurre blanc that pairs with salmon or pork; and for a brunch sauce, substitute Champagne for white wine and add a whisper of grated Gruyere for an elevated eggs benedict hollandaise substitute.