Beurre blanc literally translated from French as "white butter"
is a hot emulsified butter sauce made with a reduction of vinegar and/or white wine and grey shallots into which cold, whole butter is blended off the heat to prevent separation.
The small amounts of lecithin and other emulsifiers naturally found in butter are used to form an oil in water emulsion. Although similar to hollandaise in concept, it is not considered either a classic leading or compound sauce. This sauce originates in Loire Valley cuisine.Preparation:
A good beurre blanc is rich and buttery, with a neutral flavor that responds well to other seasonings and flavorings, thereby lending itself to the addition of herbs and spices. It should be light and airy yet still liquid, while thick enough to cling to food. Beurre blanc is prepared by reducing wine, shallots, and herbs, if used, until it is nearly dry.
Although not necessary, cream can be added at this point to act as a stabilizer to the sauce. Lemon juice is sometimes used in place of vinegar, and stock can be added as well. Cold, one-inch cubes of butter are then gradually incorporated into the sauce as the butter melts and the mixture is whisked. The sauce can separate by either overheating or cooling. If it heats past 58 °C, some of the emulsifying proteins will begin to break down and release the butterfat they hold in emulsion. If the sauce cools below 27 °C, the butterfat will solidify.
Recipe for Beurre blanc Link 1 Link 2 Link 3