Beurre Blanc Sauce

From the Thermador Kitchens

3 tablespoons white wine vinegar
3 tablespoons white wine
1 tablespoon shallots
4 ounces cubed chilled butter
1 teaspoon tarragon, minced
lemon juice

In a saucepan, reduce vinegar, wine and shallots over high heat until nearly dry. Turn heat to extra low and add in butter, one cube at a time, whisking to combine. Stir in tarragon and a small amount of lemon juice. Serve over salmon wellington or vegetables, meats and anything else that suites your fancy.