Combine all ingredients in a resealable plastic bag. Squeeze out as much air as possible and marinate the steak in the refrigerator at least 8 hours or overnight. Remove the meat from the marinade and place on the grill. Grill to desired temperature; medium-rare is best.
Core and slice a fresh pineapple into 1/4-inch rectangles. Melt 3 tablespoons of butter. Place pineapple rafts on the grill and brush with melted butter. Grill until warm, with nice grill marks.
Serve with the grilled beef, if desired, garnished with scallions.