You can make this pie extra special in autumn when wild mushrooms (the season permitting) are abundant. Pine mushrooms would be a perfect addition to the mix, but don’t dice them till they’re unrecognisable, slice them thickly to add texture and distinctive flavour.
Season the chicken thighs and brown, skin-side down with a little oil in a large pan over medium heat – about 8 minutes. Flip over and add the hot stock. Simmer gently for 25 minutes or until the thighs are cooked.
Remove the cooked chicken and strain the stock. Return the stock to the stove, skim off most of the fat and reduce to approximately 400 ml.
For the filling, in a non-stick pan add about 50ml of oil, the onion, garlic and leeks and cook for around 10 minutes over a slow heat to caramelize and soften.
Add 25 grams of butter, the diced mushrooms and thyme and cook for a further 5 minutes, season with salt and pepper.
Preheat the oven to 190°C fan-forced or 210°C conventional.
In a medium pot, melt 40g of butter over a medium heat until starting to sizzle, add the flour and stir to make a roux. Cook for one minute, stirring all the time and then add the strained stock. Cook for 2-3 minutes at a simmer whisking constantly, it should be smooth and thick.
Take the sauce off the heat and leave to cool a little. Whisk in the double cream and Dijon, add the mushroom mix, parsley and peas. Tear up or chop the chicken and add to the mix, combine thoroughly, check and adjust the seasoning – the mix will be quite thick but luscious.
Cut the pastry sheet 3 cm larger than your dish. Brush the edge of the dish with the egg, tip the filling in and drop the lid on, crimp in to seal and decorate with the pastry scraps. Make an incision in the top to release steam and brush with egg. Bake for 30-35 minutes or until golden and puffed.