London broil is a tasty form of preparation for a lean, tougher cut of meat, such as a flank steak. London broil is pan-cooked for a brief amount of time so that the meat is medium rare. Overcooking causes the meat to toughen.

Marinate the steak for two to three hours up to overnight in your refrigerator. Pour the marinade into a resealable bag. Add the steak. Shake once or twice to ensure the marinade fully covers the steak.

Grill the steak on high for three minutes on each side. Turn the grill down to medium and cook each side for another three minutes. Average temperature inside the steak should be 125 to 145 degrees Fahrenheit.

Wait five to 10 minutes before cutting the steak. If you cut too soon, all of the juices will run out of the steak, leaving you with a dry piece of meat.

Slice the beef thinly at an angle and against the grain to make the tougher cut of meat easier to chew.