1-Preparing the Chicken: Begin by seasoning your chicken breasts with salt and pepper. Place them in a pot and cover with water, then simmer until just cooked through. The key here is not to overcook the chicken, as it will continue to cook when the pie bakes. Once cooked, remove the chicken and chop it into bite-sized pieces. Important: Don’t discard the cooking water! This flavorful liquid will be used later to create the sauce base.

2-Creating the Flavorful Filling: In a large saucepan, melt the butter over medium heat. Add the chopped onion and sliced celery, cooking until soft and translucent. This step builds the flavor foundation of your filling. Once the vegetables are softened, sprinkle in the flour and stir continuously for about a minute to cook out the raw flour taste. Add your seasonings: salt, pepper, garlic powder, celery seed, and the bouillon paste or cube. Stir well to combine. Now comes the crucial step: slowly pour in the reserved cooking water and milk, whisking constantly to prevent lumps. Continue stirring and simmering until the mixture thickens to a creamy consistency.

3-Assembling the Filling: Stir in the chopped chicken and frozen mixed vegetables, combining everything evenly. Allow the filling to cool slightly before assembling the pie. This step is important as it prevents the bottom crust from becoming soggy during baking.

4-Constructing the Pie: Roll out the bottom crust and carefully place it in a 9-inch pie pan. Pour the cooled filling mixture into the crust. Roll out the top crust and place it over the filling. Seal the edges by pressing the top and bottom crusts together, then crimp with your fingers or a fork for a decorative finish. Cut a small slit in the center of the top crust to allow steam to escape during baking.

5-The Finishing Touch: Beat the egg with the tablespoon of milk to create an egg wash. Brush this mixture over the top crust to achieve a beautiful golden finish. Bake at 425°F for 40-50 minutes until the crust is golden and the filling is bubbly. If the crust begins to brown too quickly, cover it loosely with foil.

6-Serving Your Creation: Allow the pie to cool for 15-20 minutes before serving. This resting period helps the filling set and makes slicing easier. The result should be a perfectly balanced chicken pot pie with a creamy, flavorful filling encased in a flaky, golden crust.