Combine wine, vinegar, and shallots in a saucepan. Reduce until about 1 fl oz (30 mL) liquid remains.
Cut the butter into small pieces.
Add the butter to the hot reduction. Set pan over moderately high heat and whip vigorously. When butter is nearly all melted and incorporated, remove from heat and continue to whip until smooth.
Season to ta
Per 1 fl oz (29.57 mL): Calories, 210; Protein, 0 g; Fat, 23 g (94% cal.); Cholesterol, 60 mg; Carbohydrates, 1 g; Fiber, 0 g; Sodium, 240 mg.