Beurre blanc

Beurre blanc is a warm emulsified butter sauce made with a reduction of vinegar and/or white wine and shallots into which softened whole butter is whisked in off the heat to prevent separation. The small amount of emulsifiers naturally found in butter are used to form an oil-in-water emulsion. Although similar to hollandaise in concept, it is considered neither a classic leading nor compound sauce. This sauce originates in Loire Valley cuisine.