1. Preheat the oven to 220°C/Fan 200°C/Gas 7. Trim any visible fat off the bacon rashers and cut them into strips about 1.5cm wide. Mist a large non-stick saucepan with oil and place it over a medium heat. Add the bacon to the pan, then stir in the mushrooms and cook for 4 minutes, stirring regularly until they are beginning to brown.
2. Add the leek and chicken and cook for 1 minute more, stirring. Sprinkle over the flour and cook for a few seconds before gradually adding the stock, just a little at a time.
3. Bring to a simmer and season well with a pinch of salt and lots of freshly ground black pepper. Add the broccoli florets and peas and bring the water back to a simmer. Cook for 4 minutes, while stirring, until the sauce thickens, then remove from the heat and stir in the crème fraîche.
4. Divide the mixture between 4 individual pie dishes – each will need to hold about 350ml. Spray each sheet of filo pastry with oil and cut them into 4 wide strips. Working quickly, top each dish with 3 strips of the filo, oiled-side up, crumpling and scrunching them loosely as you go.
5. Place the dishes on a baking tray and bake the pies in the centre of the oven for 12–15 minutes or until the pastry is golden brown and the filling is hot and bubbling.
Recipe courtesy of Waitrose