Heat the smen or ghee in a large copper pot or heavy-based saucepan over a medium heat, stir in the onions, cumin seeds, cinnamon sticks and saffron and cook for 1–2 minutes to let the flavours mingle. Add the chicken and stir to coat well, then add the chickpeas.
Pour in the stock and bring to the boil, then reduce the heat, cover and cook over a medium heat for 15 minutes.
Add the turnips and sultanas, re-cover and cook over a medium heat for a further 10 minutes until the chicken is cooked through. Season with the salt and pepper and stir in the butter and parsley. Serve the chicken, chickpeas and turnip with couscous, if liked, pouring the sauce into a bowl to serve separately.