Flank Steak: Stir together fruit spread, vinegar, lemon juice and garlic. Place flank steak and fruit spread mixture in resealable bag; seal and refrigerate for at least 1 hour or up to 24 hours.

Compound Butter: Stir together butter, fruit spread, parsley, balsamic vinegar, garlic, salt and pepper until blended. Transfer to large piece of plastic wrap and shape into log. Roll up butter tightly in plastic wrap, twisting ends to seal. Refrigerate for 1 hour or freeze for 15 minutes or until firm. (Make-ahead: Refrigerate for up to 5 days or freeze for up to 1 month.)

Preheat grill to medium-high heat; grease grates well. Remove flank steak from marinade and season with salt and pepper. Grill, turning once, for 6 to 8 minutes per side or until instant-read thermometer registers internal temperature of 135°F (57°C) for medium-rare. Transfer flank steak to cutting board; let stand for 5 minutes. Slice thinly across the grain. Slice butter into rounds and serve over warm steak.