To cook a London Broil you will first want to tenderize the meat. Place the meat in a Ziplock bag and pour in a mixture of: 4 tsp. meat tenderizer, 2 tbsp. sugar, 4 tbsp. cooking sherry and soy sauce, 2 tsp. honey, 2 tsp. salt, and seasoned salt. Marinade 6 hours to overnight. Grill on medium heat.