Follow these straightforward steps to create your Spring Chicken Pot Pies:

1. Preheat Oven: Preheat your oven to 425°F (220°C).
2. Cook Vegetables: In a large saucepan, melt the butter over medium heat. Add onions, carrots, celery, and potatoes. Sauté until tender, about 5-7 minutes.
3. Make the Sauce: Stir in the flour, garlic powder, and thyme. Cook for about 1 minute until lightly browned. Gradually whisk in the chicken broth and milk. Bring to a simmer, stirring frequently until thickened.
4. Combine Ingredients: Add the shredded chicken and peas to the sauce. Season with salt and pepper to taste. Remove from heat.
5. Prepare Pie Crusts: Roll out one pie crust and place it in a pie dish. Pour the chicken mixture into the crust.
6. Top the Pie: Roll out the second pie crust and place it over the chicken filling. Seal the edges by crimping with a fork or your fingers. Cut slits in the top to allow steam to escape.
7. Egg Wash: Brush the top crust with the beaten egg for a golden finish.
8. Bake: Place in the preheated oven and bake for 30-35 minutes, or until the crust is golden brown.
9. Cool: Let the pot pies cool for about 15 minutes before serving. This allows the filling to set slightly.

By following these steps, you will create delicious Spring Chicken Pot Pies that are sure to impress.