2-3 lb London Broil steak
4 tbsp (1/4 cup) balsamic vinegar
2 tbsp cooking oil
2 tbsp soy sauce
1 Tbsp Dijon mustard
Lots of mined garlic
Freshly ground black pepper
1 large sprig of rosemary
coarse ground salt
1/2 cup water
1 tbsp beef bullion
1 tsp soy sauce
garlic powder and black pepper to taste
Cast iron grill plate or skillet
Mix all the marinade ingredients together. Fully immerse the steak in the marinade and refrigerate overnight. Remove from marinade an hour before cooking; pat dry and liberally rub it with salt.
Preheat oven to 350°; meanwhile, sear the steak for 5 minutes per side on a hot cast iron plate. Alternatively, you can stick it under the broiler to sear it for 5-10 minutes per side.
Then stick it in the 350° oven till it reaches an internal temperature of 122°. Let it rest for a few minutes, then slice it thin to serve. While the meat is resting you can prepare a quick au jus: bring water and beef bullion to a slow boil, add 1 tsp soy sauce, garlic powder, and black pepper, and simmer for a couple minutes.