In glass containers with lids or resealable bags, place chicken. Add balsamic vinegar, avocado oil, salt and pepper. Shake to evenly coat chicken. If using bags, massage marinade into chicken. Refrigerate at least 30 minutes and up to 24 hours.

When ready to grill, allow chicken to come to room temperature 20 minutes before grilling.

Spray or brush grill grates with avocado oil. Heat grill. (Note: Heat grill to 400 degrees F or turn dial to just above medium on gas grill.)

Cook chicken about 8-10 minutes per side or until internal temperature reaches between 165 and 175 degrees F. (Note: Give chicken room on grill; if flare-ups occur, quickly move chicken to another part of grill.)

Remove chicken from grill and rest 5-10 minutes before eating.

Cut each peach in half and remove pits. Brush each half with balsamic vinegar.

On grill grate, arrange peaches with cut side facing down. Grill 3-4 minutes per side.

To serve, arrange chicken and peaches on platter with mint leaves. Dollop whipped cream or sour cream onto each peach, if desired.