Put the bacon and thyme into a large saucepan over medium heat. Add a glug of oil and a knob of butter and let it fry off for a few minutes.

Add the leeks and let them cook for a few minutes until well coated with the butter.  Add a pinch of salt and pepper, then turn the heat down. Pop a lid on top of the pan and allow to cook down for half an hour, stirring every 5 – 10 minutes to make sure that it doesn’t burn.

Meanwhile, shred up your leftover turkey and preheat the oven to 190°C/375°F/Gas 5.

Add the turkey to the pan of now softened leeks and mix together.

Add the flour until well mixed in, then pour in the stock and stir.  Bring to a boil to heat the stock through.

Stir in the crème fraîche.  Check the seasoning and add more to taste if needed, then take off the heat.

Strain the mixture through a sieve and catch the sauce in another pan – this will be the gravy for pouring onto the pie later.

Spoon the turkey and leeks into a pie dish and set to one side whilst you prepare the pastry topping.

Dust your work surface with flour and roll out the pastry.  I buy ready-rolled puff pastry so I just unfurl it from its wrapper.  Crumble the chestnuts over one half and tear up the sage leaves and scatter them on top too. Fold the other half of the pastry over and roll the two halves together until you make your pastry big enough to cover your pie.

Lay the pastry over the top of the dish and tuck the edges around the inside of the dish and around the filling. Cut some slits across the top of the pastry, then beat up the egg and using a pastry brush wash it over the pastry which will help it go nice and golden when cooking.

Bake in the preheated oven for 35-40 minutes or until the pastry is puffed and golden.

About 5-10 minutes from the end of cooking time heat up the gravy (that you saved earlier) in a pan over low heat.

Serve with the gravy and peas (or veg of choice). The pie is so filling, it doesn’t need potatoes! Enjoy!