From Wikipedia … London broil is a North American beef dish made by broiling or grilling marinated flank steak, then cutting it across the grain into thin strips. The origin of the name is obscure; ironically, the dish is unknown in the English city of London. Many American butchers label a cut of meat “London broil.” This is confusing as the term does not refer to a specific cut of meat, but a method of preparation and cookery. The cut of meat traditionally used is flank steak, but in recent years butchers have labeled top round roast as London Broil.
Since the London Broil does originate from a tougher cut of beef, it must be marinated to help break down those tough fibers, therefore making it more succulent and tender. We really like London Broil grilled. It goes equally well with summer side dishes such as potato or pasta salad, but also delicious with cream cheese mashed potatoes and grilled or steamed veggies.
1 – 2-3 lb. top round roast (or flank steak)
1/2 cup oil
1/2 cup soy sauce
1/4 cup lemon juice
2-3 tbls. Worcestershire sauce
2-3 tbls. prepared mustard
2 tbls. minced garlic
1/2 tbls. course-ground pepper
Combine all ingredients, except beef, in a bowl, whisking to blend.
Pierce beef at 1″ intervals with the tines of a fork. Place beef in a large zip-loc bag and pour in marinade. Seal bag and lay flat in the refrigerator, evenly distributing the marinade over the beef. Chill at least 24 hours, or up to 48 hours, turning bag occasionally. This will insure the beef is equally marinated. Before grilling let it sit out for 30 minutes on your kitchen counter-top to bring to room temperature. This insures more even cooking.
On your grill, over high heat, sear London Broil 2-3 minutes per side, reduce heat to medium-off-medium on a 3-burner grill and continue to cook approx. 6 minutes per side or until internal temperature is 125-130 (medium rare).
Be careful to not overcook as the meat will continue to cook some while resting.
Allow London Broil to rest for 10 minutes after cooking to allow juices to redistribute.
London broil should be sliced across the grain to break muscle fibers and lessen tough texture.
*Note – marinade can be made up to one week in advance and stored in your refrigerator.