1. Preheat the oven to 220°C on bake, or 200°C on fan bake.
2. Melt butter in a large saucepan over a medium heat. Add the onion and cook for about 2 minutes until softened.
3. Add the flour and mix constantly until the butter and flour are combined into a paste. While continuing to stir, pour in the chicken stock and cream gradually. The paste should loosen and once all stock and cream has been added you should have a smooth gravy-like sauce.
4. Bring to a boil, then immediately reduce the heat to low and simmer for 2-3 minutes.
5. Add your herbs, frozen vegetables and shredded chicken and stir to combine. Season to taste with salt and pepper and remove from the heat.
6. Add your filling to a ceramic or glass baking dish, then cut your puff pastry sheet(s) to size for the pie top, leaving a little extra around the edges. Press or crimp the edges to the rim of the baking dish to create a seal. Add a couple of slashes, or prick the pie top with a fork to create a steam vent.
7. Brush the pastry with the beaten egg. This creates a nice shiny finish after baking.
8. Bake the pie for 25-35 minutes, until the pastry is puffed up, golden brown and shiny. 

Tips

Filling still not thick enough? Use a bit of cornstarch to thicken it further. Stir 1 to 2 teaspoons of cornstarch into cold water and gradually add to your mixture to thicken.

FAQs

How do you keep chicken pot pie from getting soggy?

Egg wash is often used to promote browning and add a subtle shine to your baked goods. But you can also use it to create a slick barrier between your chicken pot pie crust and its filling to avoid sogginess.

How long can chicken pot pie be left out?

No more than 2 hours. With creamy sauces, it’s important to refrigerate or freeze to avoid perishable foods growing bacteria.