Mix together all ingredients except flank steak.
Reserve 1/3 of the marinade for the steak once its cooked.
Put flank steak in baking dish or dish big enough to hold steak and marinade.
Marinate at least four hours up to overnight.
Heat grill to HOT. 500 degrees F.
Sear on one side about ten minutes. Turn over for about five minutes, until steak reaches 115 degrees F. at the thickest part.
Rest steak for ten minutes.
Slice against the grain on the diagonal. Pour reserved marinade.