Creating this delicious Chicken Pot Pie begins with simple steps that ensure success every time:

1. Preheat Oven: Preheat your oven to 425°F (220°C).
2. Cook Chicken: In a saucepan, boil chicken breasts in water until fully cooked. Shred the chicken and set aside.
3. Sauté Vegetables: In a large skillet, melt the butter over medium heat. Add chopped onions and diced carrots, cooking until soft.
4. Thicken Sauce: Stir in flour, cooking for an additional minute. Gradually whisk in the chicken broth and milk, stirring constantly until thickened.
5. Add Chicken and Veggies: Mix in the shredded chicken, peas, corn, potatoes, garlic powder, thyme, rosemary, salt, and pepper. Cook for 5 minutes and then remove from heat.
6. Prepare Pie Crust: Roll out the bottom pie crust and place it in a 9-inch pie dish, trimming the excess around the edges.
7. Fill Pie: Carefully pour the chicken mixture into the crust, spreading it evenly.
8. Top Pie: If using a top crust, roll it out and place it on top of the filling. Seal the edges by crimping them together.
9. Cut Vent Holes: Cut a few slits in the top crust to allow steam to escape during baking.
10. Apply Egg Wash: (Optional) Beat the egg and brush it over the crust for a golden finish.
11. Bake: Place the pie into the preheated oven. Bake for 30-35 minutes, or until the crust is golden brown.
12. Cool and Serve: Once baked, allow the pie to cool for a few minutes before slicing.

These detailed steps will guide you in creating your Chicken Pot Pie with ease and confidence.