Tomato saffron chicken

Preheat the oven to 160°C.
In a casserole, arrange free-range chicken, quartered onion, chopped leeks, bay leaves, carrots, cut into chunks, roughly chopped sticks celery, whole peppercorns and cloves garlic.
Add chicken stock, the zest and juice of 1 lemon and butter.
Cover and cook in the oven for 2 hours, or until the chicken is cooked through.