1/4 cup balsamic vinegar
2 Tbs olive oil
1/2 tsp garlic powder
1/4 tsp salt
1/4 tsp freshly-ground black pepper
4 boneless skinless chicken breast halves


Combine all the ingredients in a large resealable plastic storage bag; mix well. Seal and marinate in the refrigerator for 30 minutes.
Heat a grill pan over medium heat until hot. Place the chicken on the pan, discarding excess marinade, and cook for 6 to 10 minutes per side, or until no pink remains and the juices run clear.