Serve this marinated beef flank steak with the rich mushroom sauce for a hearty but low-calorie dinner.
To grill, prepare and marinate steak as above. Drain steak, reserving marinade. For a charcoal grill, grill steak on the rack of an uncovered grill directly over medium coals until steak is desired doneness, turning and brushing once with marinade halfway through grilling. [Allow 14 to 16 minutes for medium-rare (145 degree F) and 16 to 21 minutes for medium doneness (160 degree F)]. For a gas grill, preheat grill. Reduce heat to medium. Place steak on grill rack over heat. Cover and grill as above. To serve, thinly slice steak diagonally across the grain. Serve with Mushroom Gravy.