Serve with steak, sweetbreads, chops, or game. For Sauce Bordelaise, omit the butter and swirl in ¼ cup diced prepared beef marrow just before serving.
Combine in a small heavy saucepan over medium-high heat:
Bring to a simmer and cook until reduced by three-quarters. Strain through a fine-mesh sieve into a medium saucepan. Place over medium heat and stir in:
Simmer for 15 minutes. Just before serving, stir in: