Blues BBQ, Inc.

Ingredients:

1 1/4 pounds flank steak
3 medium onions, cut into 1/2-inch slices
1/4 cup balsamic vinegar
2 teaspoons Dijon mustard
1 teaspoon salt
1 teaspoon rosemary, crumbled
1 teaspoon olive oil

Preparation:

Combine vinegar, mustard, salt, rosemary and oil in large, shallow glass dish. Add steak and onions; turn to coat. Let stand 15 minutes. Grill steak and onions 8 to 12 minutes, turning once and brushing with marinade. Slice steak across the grain. Serve with onions.