Combine the olive oil, balsamic vinegar, garlic, basil, sea salt, and freshly cracked pepper, to taste, together in a large zip lock bag. Mix until well combined then add the chicken breasts to it, seal and place into the refrigerator for 2-24 hours.

Remove the chicken from the refrigerator 20 minutes prior to grilling.

Coat the grill rack with cooking spray then heat on high. Place the chicken on the grill rack and cook 4-6 minutes per side or until cooked through and the juices run clear. Let the chicken rest for 5-7 minutes before slicing and serving with a little more chopped basil sprinkled on top. Enjoy.