Creamy chicken, leek, bacon and thyme pie

Method

1. Place the chicken in a large heavy-based saucepan or flameproof casserole over a high heat. Add the carrot, 1 onion and the bouquet garni. Pour over enough cold water to cover the chicken. Cover with a lid and bring to the boil, then remove the lid and simmer over a gentle heat for 45 minutes.
2. Remove the chicken from the pan and set aside. Place the pan back over a high heat, then boil for 30 minutes to reduce to a good stock.
3. Meanwhile, remove the meat from the chicken and tear into bite-size pieces. Add the bones to the boiling stock as you go, to enrich the flavour.
4. In another large saucepan, heat the olive oil over a medium heat, add the remaining onion and the leek, season and fry for 5 minutes, stirring frequently. Add the lardons, then continue frying until the veg and lardons are golden. Remove from the pan and set aside.
5. Strain the stock, discarding the veg and bones. Measure out 1.5 litres stock and set aside. (Cool and freeze any leftover stock.)
6. Melt the butter in the pan in which you cooked the bacon, then add the flour and stir to make a smooth paste. Gradually add the reserved stock, a little at a time, stirring until the mixture is smooth. Place over a medium heat and bubble for a few minutes to cook the flour. Add a little more stock if the sauce is too thick.
7. Stir in the crème fraîche, mustard and reserved thyme leaves. Season. Add the shredded chicken, bacon, onion and leek. Stir until well mixed.
8. Divide the chicken mixture evenly between 2 x 2 litre rectangular pie dishes and leave to cool completely.
9. Brush the edges of the pie dishes with beaten egg, place the puff pastry over the top, press down the edges and seal with a fork. Cut off the excess pastry with a sharp knife, roll out on a lightly floured surface, then cut out small leaves to decorate the top of the pies. Make a small hole in the top of each pie to let out the steam (or use a pie funnel if you have one). Place in the fridge and chill for 20 minutes. Preheat the oven to 200°C/fan180°C/gas 6. Brush one pie with beaten egg.
10. Wrap the other pie in cling film and foil. Freeze for up to 1 month.
11. To cook the freshly made pie, place on a preheated baking sheet and bake for 20-25 minutes until golden brown and bubbling. Serve with buttered peas.
12. To cook the frozen pie, defrost thoroughly overnight, brush the pastry with beaten egg, then bake for 30-35 minutes until brown and bubbling. Serve as in step 11.