Slash each piece of chicken 2–3 times with a small knife. Mix together the spices and half the olive oil, rub over the chicken pieces, cover and marinate in the refrigerator for at least 2 hours, preferably overnight.
Heat the remaining oil in a tagine or large flameproof casserole, add the chicken pieces and fry for 4–5 minutes until golden all over. Add the onion, garlic and fennel to the pan and continue to fry for 2–3 minutes.
Add all the remaining ingredients, except the coriander, and stir well. Cover and simmer for about 1½ hours or until the chicken begins to fall off the bone. Season well and stir in the coriander.