Preheat oven to 375.
Add chicken, onion, and garlic to saucepan. On medium-high heat, cook for 3-4 minutes.
Add potatoes and frozen vegetables to saucepan. Cook for 5 minutes, until potatoes start to brown.
Add all seasonings. Add chicken stock. Let simmer for 5 minutes.
Add flour slowly while constantly stirring mixture. This will thicken the sauce.
Remove from heat. Let mixture cool for 5-10 minutes. Prepare pie crust in pan.
Add mixture to pie pie. Top with remaining crust. Cut a few slits at the top of the pie.
In a small bowl, beat an egg with water. This creates an egg wash. Brush on the top of the pie crust.
Bake at 375 for 30 minutes.