Flank Steak with Cilantro & Blue Cheese Butter

In a shallow dish, combine the first five ingredients. Add steak; turn to coat. Cover and refrigerate 2-4 hours., Drain beef, discarding marinade. Grill steak, covered, over medium heat or broil 4 in. from heat 6-8 minutes on each side or until meat reaches desired doneness (for medium-rare, a thermometer should read 135°; medium, 140°; medium-well, 145°). Let steak stand 5 minutes before thinly slicing across the grain., In a small bowl, beat blue cheese butter ingredients until blended. Serve steak with butter.