1. Get your chicken onto some greaseproof paper (as you can then get your hands into it) and season with plenty of salt and pepper and sprinkle with half of your thyme. Ensure all of the chicken is seasoned well.
2. In a casserole, heat the olive oil and pan fry your chicken over a high heat just to get some colour on it. The fat will render out of the chicken. Remove from the pan and put to one side, leaving your pan on the heat.
3. Add your onions and mushrooms to the pan and stir them around to soften then reduce the heat to medium-low. Cook for around 10 minutes.
4. Add the remaining thyme, tomato purée, white wine and the chicken stock and give it all a good stir.
5. Return the chicken to the pan and bring it to the boil then turn down to simmer. Place the lid on the casserole and continue to cook for an hour so the sauce thickens and the chicken falls off the bone with a little push with a fork.
6. Scatter over the parsley and stir it in then serve it up in large bowls and tuck in with some fresh bread.