In a saucepan over medium high heat, combine wine, vinegar and shallots. Reduce until almost a syrup consistency. Add cream and continue to cook reducing by half. Turn the heat to low, add butter cubes 2 at a time while stirring, until the butter is added, and the sauce is a creamy consistency. Season with pepper and salt.
If the butter is not chilled it will not incorporate into the sauce. Also, if the wine mixture is not reduced far enough the sauce will be runny.
A good sauce for the scallops or fish.