Method

1. Preheat the oven to 190°C / 375°F / Gas Mark 5
2. Heat the margarine in a pan. Add the onion, garlic, leek and mushrooms and sauté for 2 to 3 minutes until softened but not coloured
3. Stir in the flour and cook for 2 minutes, stirring continuously
4. Gradually pour the stock into the pan followed by milk stirring until smooth after each addition
5. Add the bay leaf, bring to the boil and then reduce the heat and simmer for 5 minutes until thickened and slightly reduced, stirring occasionally
6. Stir in the parsley, season to taste and set aside to cool
7. Cover with a greased circle of non-stick parchment paper to prevent a skin forming
8. Place the cooked turkey into a 1¾ litre / 3 pint pie dish and ladle over the leek sauce
9. Stir gently to combine
10. Roll out the pastry into an oval shape the size of the dish; it should be ½ cm / ¼ inch thick on a lightly floured work surface - make sure that it is large enough to hang over the edges of the dish
11. Place the pastry lid on top of the pie, trimming it down to fit and brush around the edges with a little water to help it stick, then press down along the sides to seal
12. Cut a small slit in the pie lid to allow the steam to escape and with the trimmings of the pastry you could cut out a few leaves to decorate the top
13. Brush with the beaten egg and bake for 45 minutes to 1 hour or until the pastry is puffed up and golden brown