In a large pan, place the chicken, potatoes, onions, red pepper, and the optional ingredients (if you're using them), and drizzle all the spices and olive oil on top, and mix well to coat everything (I recommend doing this with latex gloves as the turmeric can be a real pain to take off of skin!).
Relayer so that the chicken skin side is up and that all the chicken is on one layer. Add the tomato slices (or whole cherry tomatoes).
Cover with aluminum foil and bake for about an hour. Baste with juices mid-way if you like, and ensure the chicken is cooked all the way through (may need more time if pieces are large).
It's ready when a fork easily breaks the potatoes, and the chicken is soft.
Remove foil, and broil for 3-5minutes until chicken skin and potatoes are crispy on top (careful not to burn!).