Heat the oven to 200C/180C fan/gas 6. Heat the oil in a large, lidded pan over a medium heat and fry the chicken and bacon until browned (the chicken does not need to be cooked through at this stage). Remove from the pan, leaving the oil behind, and set aside.

Tip the onion, carrots, celery, bay leaf and thyme into the pan, reduce the heat to medium-low, and cook with the lid on, stirring occasionally, for 10-12 mins until the carrot has softened a little and the onion is softened but not golden. Stir in the wine and cook for 2-3 mins to reduce a little. Tip the cooked chicken and bacon back into the pan and mix together. Stir in the mustard, then the flour, and cook for 1 min before pouring in the stock. Season, mix well and bring to a simmer. Reduce the heat and stir in the cream. Bring back to a simmer then turn off the heat and pour the mixture into a large ovenproof dish (ours was 23cm). You can freeze the filling at this stage for up to three months, defrost fully and continue making the pie.

Unwrap the puff pastry and, if needed, roll out a little more to ensure it will cover the dish. Cover the pie dish and remove any excess pastry before crimping the edges using your fingers. Use any excess pastry to decorate the top of the pie. Glaze the pastry all over with beaten egg, poke two holes in the top to allow steam to escape, then bake for 30-40 mins until golden. The pie can be frozen, unbaked, for up to three months. Cook from frozen for 1 hr-1hr 15 mins. Ensure it’s fully cooked through and cover with foil if it’s browning too much. Serve with peas or broccoli, if you like.