Broil: Let the London broil come to room temperature, about 40 minutes. Preheat the broiler and pan for 10 minutes. Slide the broiler pan out of the oven and put the steak on the pan. Put the pan back in the top rack slot. Your broiler pan should sit about 4 inches from the flame. London broil only needs 4 - 5 minutes of cooking time on each side. Set a timer to help you remember when to flip it. An 8 minute steak will cook to rare while 10 minutes gives you a medium-rare steak. Remove the meat from the oven and let it rest for 5 minutes before carving. Grill: Let the London broil come to room temperature, about 40 minutes. Preheat grill to medium and place London broil on the grill. Cook uncovered for 2 - 3 minutes per side for a rare steak, 4 - 5 minutes per side for a medium steak and 5 - 6 minutes per side for a well done steak. Internal temperature should read 135 degrees for medium rare and 145 degrees for medium to well done. Allow London broil to rest for 5 minutes before carving.