For the marinade:
Place all marinade ingredients into a medium bowl and whisk.
Rinse the chicken breasts under cold water, place them in a large, resealable plastic bag and pour in the marinade.
Press the air out of the bag and seal tightly.
Turn the bag several times to distribute the marinade, place the bag in a bowl and refrigerate for 3 to 4 hours.
Remove the chicken breasts from the marinade and reserve the marinade.
Pour the marinade into a small saucepan and boil for a minute.
Barbecue the breasts, skin side down first, for 5 to 6 minutes each side or until the meat is firm and the juices run clear.
Baste with the boiled marinade once, halfway through cooking.