Actually, London broil is tricky because you never know how tough it's going to be. In your place I'd slice it into thin pieces, marinate it in either a store bought or homemade marinade (Quick teriyaki -- equal parts soy sauce, brown sugar, and sake, sherry, or white wine. Some ginger if you have it.) Let it sit for an hour and then cook it in a frying pan. Serve with rice.