Preheat the oven to 190°C. Melt the butter and half the oil in a frying pan over low heat then fry the onion, celery and salt for about 15 minutes or until very soft. Add the pine nuts and cook for a further 5 minutes. Set aside to cool.
Add the artichokes, parmesan, breadcrumbs and egg to the cooled onion mix and season with freshly ground black pepper. Set aside.
In a small bowl, mix together the basil, thyme, garlic, zest and season with salt and pepper. Add the remaining oil, and continue to mix. Gently slide your hand under the skin of the chicken to loosen, trying to get into the leg and thigh and being careful not to split the skin. Massage in the herb and oil mixture, rubbing it over and under the skin.
Stuff the chicken cavity with the artichoke mix (don’t pack too much in – you can cook the remainder separately). Tie the legs together then place the chicken in a roasting dish and cook for 1¼ hours, basting occasionally, or until cooked through. About halfway through the cooking, form the remaining stuffing into rough balls and place around the chicken to cook. Serve with roast vegetables.