Chicken pot pie

1 cup chopped onions
1 cup chopped celery
1 1/2 cups diced potatoes
1 (16 ounce) bag frozen mixed vegetables, thawed
1/2 cup butter
1/2 cup all-purpose flour
2 cups chicken broth
1 cup half-and-half
1 teaspoon salt
1/4 teaspoon pepper
4 cups chopped cooked chicken
2 (15 ounce) packages refrigerated pie crusts

Saute potato in margarine for 5 minutes in a dutch oven. Add onion, celery and thawed frozen vegetables. Saute for another 10 minutes. Add flour gradually to the sauteed mixture, stirring constantly for one minute.
Allow refrigerated pie crust to come to room temperature. Meanwhile, combine half and half and chicken broth. Gradually stir into the vegetable mixture. Cook over medium heat, stirring constantly, until thickened and bubbly. Stir in salt and pepper. Add chopped chicken, stirring well. Add additional salt and pepper to taste.
Preheat oven to 400°.
Spray nonstick spray into a 9 X 12 casserole. Place pie crust on the bottom of the pan to cover, cutting to fit. Pour chicken/vegetable mixture over the pie crust, then top with the remaining pie crust. Cut vents into the top crust.
Bake for 40 minutes or until crust is golden brown. Enjoy!