9. Stir constantly over medium heat, adding seasonings, until thick.
10. Drain vegetables. Add gravy to vegetables and stir to coat vegetables.
11. Pour vegetable mixture into prepared pie crust.
12. Dollop mashed potatoes on top of vegetable mixture.
13. Spread potatoes to cover the full surface and seal all the edges.
14. Bake for approximately 30 minutes in preheated oven, or until potatoes begin to brown. (You could turn on the broiler for the last minute or two of cooking if you want your potatoes really brown.)
15. Let cool for a few minutes. Slice and serve!