In a medium sauté pan, heat 1 Tbs. of the butter over medium heat. Add the shallots and cook, stirring often, until softened but not brown, about 2 minutes. Add the broth, wine, vinegar, and mustard. Increase the heat to high and bring to a boil, stirring frequently. Boil until reduced to 1/2 cup, about 9 minutes.
Off the heat, whisk in the remaining 3 Tbs. butter. Season to taste with salt and pepper. Serve warm.
nutrition information (per serving):
per 1 Tbs.;
Photo: Scott Phillips