Don't use this.
Our Champagne Beurre Blanc is probably a little misleading. It is not made with the infamous sparkling wines of Champagne but it is made with Champagne vinegar. This vinegar like its sparkling wine cousin should only be called Champagne if it is produced within the viticultural region of Champagne. These Champagnes typically will shown Reims or Epernay as their point of origin. Originally we did use a sparkling wine, one from Limoux, but found the subtlety of the sparkling wine was lost with the intensity of the vinegar. So we switched to a French chardonnay.
Champagne vinegar is often considered the 'king of vinegars' in France, its production process is unique and includes a carefully monitored aging in small oak barrels.
Another point one could nitpick is that we add heavy cream to our beurre blanc. I believe beurre blanc with the addition of cream is more accurately called beurre nantais. The heavy cream while unnecessary does improve the stability of the sauce. During the course of a busy restaurant service, having a stable sauce in an unstable environment is highly valued.
Classicly, butter is added slowly in little pieces over low heat. We have found that it can be done by adding the butter all at once.
2 shallots, finely chopped
1/4 cup champagne vinegar
1/4 cup white wine
3 tablespoons heavy cream
1/4 pound butter, cold
Salt and cayenne
In a saucier, slowly reduce vinegar and white wine with shallots until dry. Over medium heat, add heavy cream and butter. Whisk constantly until butter is melted, emulsified and warm. Do not bring this to a boil, it will break. Season to taste.
Fresh cut herbs added to the sauce greatly improves the sauce's dimension.