Preheat the oven to 190C/170C fan/340F. Line a deep baking dish with a sheet of shortcrust pastry. Press the pastry carefully to the sides and the bottom of the dish, so that there are no gaps (air bubbles). Pierce the pastry in a few spots with a fork and blind bake it for 10-15 minutes or until golden. (Skip this step if using only 1 layer of pastry on top.)

Meanwhile, dice the chicken thighs and gammon steak (ham). Add rapeseed oil to a large frying pan, set it on medium-high heat and add the meat once hot. Sear the meat from all sides. Add 100ml of water, and a chicken stock cube. Cover and cook for 15 minutes.

Peel and slice the leek and fry it in butter on medium heat. Let it soften, but do not let it caramelise (brown). Once the leek is soft, add plain flour, stir and fry for 1 minute. Gradually add milk, stirring the sauce as it thickens. When the sauce is thick (it will have a yogurt or crème fraiche-like consistency), season it with thyme, nutmeg, black pepper and salt and stir in the cooked chicken and ham with juices, mix until combined.

Take out the pre-baked pastry, and top it with the chicken, ham and leek mix. Cover it with another layer of pastry and brush it with a beaten egg. Cut a small hole in the middle of the pie. And return it to the oven. Bake it for 25-35 minutes on 170C/340F at the bottom of the oven.