Source: dLife

Flank steak with dijon mustard, and vidalia onion on top.

Servings

1.5 lb Beef, flank steak, london broil, lean, raw, 0" trim
1 tbsp dijon mustard
0.25 cup cider vinegar
1 tsp salt
0.5 tsp black pepper
1 medium onions , thinly sliced (Vidalia)
1 cooking spray

1 Remove any visible fat from the steak and place the steak in a flat glass pan.
2 In a small bowl combine the mustard, vinegar, salt, and pepper and pour over the steak. Refrigerate, covered, for 30 minutes.
3 Coat the grill with cooking spray and preheat for 5 minutes. Grill the steak for 4 minutes. Flip over and add the sliced onions and continue grilling for 3 to 4 minutes, or until desired doneness.
4 Slice the beef thinly across the grain and serve topped with the onions.

Delicious recipe.