Rinse and pat dry chicken breasts with paper towels. Place in large zip-top bag. Add raspberries, vinaigrette, vodka, if using, and chopped mint. Squeeze air out and seal bag. Gently massage the bag to mash raspberries. Marinate in the refrigerator for 1 to 4 hours.
Preheat grill to medium-high and oil the grates.
Place the chicken breasts on the grill and cook for 4 to 6 minutes per side. Remove from grill and place on serving platter. Garnish with fresh mint sprigs and fresh raspberries.
