In a small bowl, stir together the lemon juice and mustard. Trim away most of the fat from the steaks, and rub with the mustard marinade. Place into a resealable bag, and marinate in the refrigerator for at least 1 hour, and up to 24 hours.
Preheat a grill or large skillet for medium-high heat.
Grill or fry steaks for about 5 minutes per side, or to your desired degree of doneness. Remove from the heat, and let the meat rest for 5 to 10 minutes to let the juices settle. Cut each steak along the grain into 3 or 4 pieces. Serve with blue cheese dressing.