In a large skillet over medium heat, melt the butter. Add the chopped onion, carrots, and celery, sautéing until the vegetables are tender (about 5-7 minutes).
Sprinkle in the flour, stirring constantly for about 2 minutes to form a roux, ensuring it’s well mixed with the vegetables.
Gradually whisk in the chicken broth, followed by the milk, mixing until smooth.
Add the shredded chicken, peas, thyme, garlic powder, salt, and pepper to the mixture, stirring to combine. Allow it to simmer for about 5 minutes until it thickens slightly.
Remove the skillet from heat and allow the filling to cool while you prepare the crust.
Roll out one pie crust and fit it into a 9-inch pie pan. Pour the filling into the crust.
Cover with the second pie crust, crimping the edges to seal. Cut a few slits in the top to allow steam to escape.
Beat the egg in a small bowl and brush the mixture over the top crust for a golden finish.
Bake in the preheated oven for 30-35 minutes, or until the crust is golden brown and the filling is bubbling.
Allow to cool for 10 minutes before slicing and serving.
Notes
Serve slices of the pot pie on individual plates, garnished with fresh parsley for added color. Consider pairing it with a simple side salad for a complete meal.