Creating the perfect Chicken Pot Pie is as easy as following these simple steps:

1. Preheat the Oven: Start by preheating your oven to 425°F (220°C).

2. Cook the Chicken: In a medium pot, add the chicken breasts and cover them with chicken broth. Simmer over medium heat for about 15-20 minutes, or until the chicken is cooked through. Remove the chicken, shred it, and set aside.

3. Sauté the Vegetables: In the same pot, melt butter over medium heat. Add onions, carrots, celery, and potatoes. Sauté for about 5 minutes until they start to soften.

4. Make the Roux: Sprinkle the flour over the sautéed vegetables and stir well to combine. Cook for an additional minute.

5. Add Liquids: Gradually add the milk and stir constantly. Pour in the chicken broth and bring the mixture to a gentle simmer.

6. Season the Filling: Add thyme, salt, and black pepper. Stir in the shredded chicken and peas once the mixture thickens.

7. Prepare the Crust: Roll out the pie crust and place it into a nine-inch pie dish. Fill it with the chicken and vegetable mixture.

8. Top the Pie: Cover the pie with a second crust. Seal the edges by crimping with a fork or your fingers. Cut several small slits for steam to escape.

9. Egg Wash: Beat the egg and brush it over the top crust to give it a golden finish.

10. Bake: Place the pie in the preheated oven and bake for 45-60 minutes, or until the crust is golden and the filling is bubbling.

11. Cool Before Serving: Allow the pot pie to cool for about 10-15 minutes before slicing.

Following these steps will guide you towards creating a delicious and comforting Chicken Pot Pie without the hassle.