Method
Prep:5min  ›  Cook:25min  ›  Ready in:30min 

1. Brown the chicken: Heat the oil in a large pan or flameproof casserole. Add the chicken, then season and cook over a high heat for 2 minutes, turning over to brown both sides. Remove from the pan and set aside on a plate.
2. Cook the vegetables: Add the mushrooms to the pan and cook over a high heat, stirring, for 1 minute. Then reduce the heat and add the leeks, laying them across the middle of the pan and moving the mushrooms to the sides. Add the turnips and potatoes in an even layer.
3. Add the stock and chicken: Pour in the stock and add the sherry. Bring to the boil. Put the chicken on top of the vegetables, adding any juices from the plate. Reduce the heat so that the stock bubbles steadily without boiling too fiercely. Cover and cook for 10 minutes.
4. Cook the beans: Add the French beans, cover and continue to bubble for a further 5 minutes or until the chicken and vegetables are cooked. Using a draining spoon, divide the ingredients among four warmed plates or transfer them to a serving dish. Keep warm while finishing the sauce.
5. Reduce the stock: Boil the cooking stock hard, over a high heat, in the open pan for 5 minutes to reduce it slightly and concentrate the flavour. Meanwhile, mix the cornflour to a smooth paste with the yoghurt and lemon zest.
6. Make the sauce: Gradually add a little and then most of the reduced stock to the yoghurt mixture, stirring, and pour it back into the pan. Bring to the boil, stirring, to thicken the sauce slightly. (The cornflour stabilises the yoghurt and prevents it from curdling.) Taste for seasoning. Pour a little of the sauce over the chicken and vegetables, and serve the remainder separately.

…another idea

Moroccan chicken stew: Add 2 crushed garlic cloves and 1 tbsp Moroccan spice mix, such as ras-el-hanout or harissa, with the mushrooms at step 2. Add 2 sliced red peppers instead of turnips, and chunks of butternut squash instead of potatoes. Pour in 300ml boiling water instead of the stock and sherry, and 2 x 400g cans chopped tomatoes. After putting the chicken thighs on the vegetables at step 3, sprinkle 2 x 400g cans chickpeas, drained and rinsed, over the top; omit the French beans. Do not reduce the cooking juices at step 5. Omit the yoghurt mixture and sprinkle with chopped fresh coriander leaves and lemon zest before serving.