1 Combine marinade ingredients and pour over the london broil in a large ziploc bag. Let the meat marinate in the fridge for at least 4 hours or longer. (Let it go overnight for maximum flavor and tenderness.)2 Preheat the grill. (This is KEY! You don''t want to put your steak on anything less than a screaming hot grill.)3 Remove the steak from the marinade, place it on the hot grill and cook the meat for about 6 to 7 minutes per side for medium, turning once. 4 Meanwhile, pour the marinade into a small saucepan and bring it to a boil. Lower the heat and simmer the marinade for 10 minutes.5 Transfer the steak to a cutting board and let it rest for 5 minutes before carving it across the grain into thin slices. Serve with marinade sauce on the side.