Sear over hot charcoal grill for one minute on each side, painting top with marinade. Discard any remaining marinade. Grill an additional 3-6 minutes a side, depending on coals and thickness. Slice thinly on an angle. Place in a serving dish, with the following sauce moderately applied, and more available on the side. Garnish with finely chopped parsley.
Sauce: Bring equal parts red wine and butter slowly to a boil. Add a like amount of chopped green onion and simmer for a minute or so.