Preheat the oven to 170°C.
Heat the oil in a large, preferably heavy- based casserole dish, then gently fry the celery pieces and the onion slices.
When the onion begins to brown, add the garlic and ginger, then stir for 1-2 minutes. Add the spices, stir for 1 minute, then pour in the stock and tomatoes.
Place the chicken pieces in the sauce, season with salt and pepper. Cover with a lid (or foil) and bake for 1 hour in the oven.
Remove the cover, brush the chick with a little oil, then turn the over in the saucepan.
Bake for 35-40 minutes (without cover) until golden and the chicken is cooked through.
Put the chicken pieces carefully into a serving dish, cover and rest whiles you reduce the sauce on the stove to a thick sauce (this should take 5- 8 minutes).
Serve with the sauce poured over the chicken.