1. Combine all ingredients except steak and parsley in a shallow baking dish. Add steak, turn several times. Cover and marinate in the refrigerator 30 minutes or up to 24 hours.
2. Heat grill.
3. Remove steak from marinade, letting excess marinade and garlic drip back into pan. (Do not discard marinade.) Grill steak 6 minutes, turn and brush with some of marinade and pieces of garlic. Grill 5 minutes. Turn steak again and grill 3 to 6 minutes more, until an instant-read thermometer reaches 140 degrees F when inserted in center of steak for medium-rare. Transfer steak to cutting board, let stand 5 minutes before slicing. Garnish with parsley if desired. Makes 8 servings.