It takes 8 to 10 minutes to cook a London broil in the oven. A London broil only needs 4 to 5 minutes of cooking time on each side. Cooking the steak 8 minutes makes it rare, and cooking it 10 minutes leaves it medium rare.
The broiler and pan should be preheated for 10 minutes before placing the steak under the broiler in the oven. A London broil is not a cut of beef, but a method of cooking it. Usually, London broil is made with tougher cuts of meat, such as the flank or top round steak.
The meat is marinated overnight. Typical marinades start with soy sauce, beer or Worcestershire sauce and also have vegetable oil and seasonings, such as red wine, balsamic vinegar, fruit juice, hot sauce and fresh ginger. Meat is marinated by poking holes in it, and then soaking it in the marinade in a sealed container. The London broil is then broiled in the oven. If the meat is overcooked, it becomes very tough. After coming out of the oven, the meat should rest for 5 minutes before being carved. For a London broil, the meat should be cut across the grain into thin slices.