To make the stuffing, heat the oil in a large non-stick frying pan over medium heat. Add the onion, Craisins, pistachio and garlic and cook, stirring, for 8-10 minutes or until onion softens. Set aside for 5 minutes to cool slightly. Place the pistachio mixture in a bowl. Add the breadcrumbs, egg and parsley and stir to combine. Season with salt and pepper.
Preheat oven to 190°C. Rinse chicken cavities under cold running water. Pat dry with paper towel inside and out.
Spoon the pistachio mixture among chicken cavities. Close cavity openings with toothpicks. Tie the legs together with unwaxed white kitchen string.
Line a large roasting pan with non-stick baking paper. Place chickens in pan and brush with oil. Season with sea salt and pepper.
Roast for 1 hour 15 minutes or until juices run clear when a skewer is inserted into the thighs. Cover with foil and set aside for 10 minutes to rest. Place chickens on serving platters and serve with pistachio stuffing and parsley.