Place the pork slices in a single layer in a shallow baking dish. In a small bowl, mix together the remaining ingredients except the butter and chives. Pour the marinade over the meat; cover and marinate in the refrigerator 2 hours.
Preheat the oven to broil. Remove the pork slices from the marinade and place on an oiled broiler pan. Pour the marinade into a small saucepan and bring to a boil over high heat.
Boil the marinade until reduced by half. Turn the heat down to low and swirl in butter a little at a time: do not allow sauce to boil after butter has been added.
Broil the pork slices 3 minutes per side. Transfer the pork to plates, allowing 2 slices per person. Spoon a little sauce over the pork and sprinkle with chives. Serve immediately.