01 - In a medium mixing bowl, whisk together soy sauce, olive oil, Worcestershire sauce, balsamic vinegar, and freshly squeezed lemon juice until fully blended.
02 - Add minced garlic, Dijon mustard, brown sugar, freshly ground black pepper, rosemary, and onion powder to the bowl. Whisk until mixture is homogeneous.
03 - Transfer steaks to a large resealable plastic bag or shallow dish. Pour marinade evenly over steaks, ensuring thorough coating.
04 - Seal the bag or cover the dish and refrigerate for at least 2 hours, preferably up to 24 hours. Turn steaks occasionally to promote even marination.
05 - Remove steaks from marinade, pat off excess liquid with paper towels, and discard any leftover marinade. Proceed to grill, broil, or pan-sear as desired.