This is a great way to use up and meat from your Sunday roast, works great with left over ham too
Fry off your leek, bacon and mushrooms in the butter and oil. When soft, Add your stock, stirring continuously then add the cream so that the sauce is rich and creamy. If the sauce is a little thick, add a splash of water.
Add your cooked chicken, and stir carefully until meat is completed coated and empty contents into a large dish. Again if you prefer to make this like a more traditional pie you can line the pie dish with the rolled out short crust/puff pastry before putting in the filling.
Cover with pastry, and make a vent in the pie top, and brush with egg yolk and Bake in oven on a high temperature, 200C for around 25 minutes or until golden.