In a medium saucepan, combine the shallots, wine and peppercorns and bring to a boil. Reduce the heat to medium-low and simmer until reduced in volume by half, about 2 minutes. Whisk in the butter, 1 tablespoon at a time, adding each piece before the previous one has been completely incorporated. Continue until all the butter is incorporated and the sauce coats the back of a spoon, removing the pan from the heat periodically to prevent the sauce from getting too hot and breaking.
Strain into a clean container and use immediately.
Yield: 1 cup