In a mixing bowl, combine the olive oil, soy sauce, balsamic vinegar, minced garlic, Dijon mustard, brown sugar, black pepper, salt, dried rosemary, and Worcestershire sauce.
Whisk all the ingredients together until well combined. Adjust seasoning to taste if desired.
Place the steak in a large plastic zip-top bag or shallow dish. Pour the marinade over the steak, ensuring it is completely covered. Seal the bag or cover the dish.
Refrigerate the steak for at least 1 hour, but ideally for 4-6 hours for maximum flavor. You can also marinate overnight.
Preheat your grill to high heat. Remove the steak from the marinade and let excess marinade drip off. Discard any remaining marinade.
Grill the steak for approximately 4-5 minutes on each side for medium-rare, adjusting time depending on the thickness of the steak and your desired doneness.
Remove the steak from the grill and let it rest for 5 minutes before slicing. Serve and enjoy!