In a small bowl, whisk together the olive oil, balsamic vinegar, garlic, Italian seasoning, salt and pepper.

Tenderize the chicken breasts using a meat tenderizer. Then place them in a Ziploc bag, and pour the marinade mixture over top. Close the bag tightly and squish it around to coat the chicken. Place the bag on a plate and marinate at room temperature for 10 minutes or in the refrigerator for up to 12 hours.

Discard the excess marinade. Clean and oil your grill grates. Then grill chicken over medium-high heat for 8-10 minutes per side, until the internal temperature of the chicken reads 160°F. This simple and inexpensive digital meat thermometer will change your grilling game forever!

Remove the chicken breasts to a platter to rest and cover with a tent of aluminum foil for 10 minutes.