Combine mustard, balsamic vinegar, olive oil, garlic, and basil in a large shallow pan. Add sea salt and pepper to taste. Whisk to combine.

Season steak with black pepper and add to the marinade. Turn steak with tongs a few times to ensure steak is evenly coated with the marinade.

Marinate for at least 30 minutes at room temperature or up to 10 hours in the refrigerator.

Heat an outdoor grill to medium heat or grill-pan on the stovetop top on medium-high.

Remove steak from marinade allowing excess marinade to drip off. Lightly season steak with salt and black pepper on the first side. Grill steak on medium 4-5 minutes. Turn steak, season with salt and black pepper to taste on 2nd side and cook for another 3-5 minutes, or until steak reaches desired level of doneness.

Transfer to a platter and let rest 10 minutes before slicing.

Slice steak and serve with Grilled Corn On the Cob With Herbed Parmesan Butter or your favorite side dish.

Enjoy!