For the marinade, mix all of the marinade ingredients together in a bowl until well combined. Add the chicken breasts and make sure theyâre well covered in the marinade. Set aside to marinate in the fridge for 12 hours, or overnight.
When the chicken has marinated, preheat the grill to its highest setting. Remove the chicken breasts from the marinade, shaking off any excess, and grill for 8-9 minutes on each side, or until the outside is golden-brown and the inside is cooked through. Baste the chicken breasts with the butter and a little lemon juice. Set aside.