Combine first 7 ingredients in a shallow dish or heavy-duty zip-top plastic bag; add steak. Cover or seal, and chill 8 hours, turning occasionally.
Remove steak from marinade, discarding marinade.
Grill, covered with grill lid, over high heat (400° to 500°) about 7 minutes on each side or to desired degree of doneness. Let stand 5 minutes. Cut diagonally across the grain into thin slices.
This is our go-to recipe for Flank Steak. We get raves from all our dinner guests.