Chicken Leftovers Pot Pie

What to do with bits of cooked chicken other than slapping them into a sandwich? Slap it in a pot pie! Even there is no stuffing in this pie, there it has a flavor similar to it, and it has just the right amount and quality of gooey sauce inside. I've made this almost as many times as I've made roast chicken. Which is often. 

1 small potato, diced

1 small onion, diced

1 stalk celery, diced

1 carrot, diced

1/4 cup (2oz/58gr) butter

1/4 cup flour

2 tsp. fresh thyme, minced

1 cup chicken broth

½ cup crème fraîche

1 teaspoon salt

1/4 tsp. pepper

2 heaping cups chicken, cooked and chopped
2 batches of pie crust, uncooked

1. Preheat oven to 400°F.
2. Sauté onion, celery, carrots and potatoes in butter until cooked through and starting to brown, about 10 minutes.
3. Add flour to sautéed mixture, stirring well. Cook one minute, at least, or until well browned. This is important - cooking the flour in the buttered vegetables means the flour is absorbing all the liquids and fats in the pan, then cooking so that when you make the sauce, it will have carried all the lovely browning flavour with it, and it won't taste floury.
4. Combine the broth and the crème fraîche. Dump into the vegetable mixture and stir thoroughly. Stir in the thyme, salt and pepper. Cook over medium heat stirring constantly until the broth thickens and gets bubbly. If you feel you haven't browned the flour mixture enough, it's not too late. Leave on a high simmer and let cook a bit more.
5. Mix in the chicken and stir to combine well.
6. In a shallow pie pan lined with uncooked dough, pour in the chicken mixture and top with the remaining pie dough. Cut slits in the crust to allow steam to escape. Bake for 40-50 minutes or until the pastry is golden brown and the filling is bubbly and heated through.