Turkey Pot Pie

1 pie crust 
4 tablespoons butter
1/2 cup onion, chopped fine
1 medium carrot, sliced or diced
1 stalk celery, chopped fine
2 heaping cups leftover turkey, cubed 
1/4 cup all-purpose flour
2 1/2 cups turkey broth, if you have it, or chicken broth
1/4 cup heavy cream
1 cup peas 
2 teaspoons fresh herbs, chopped, i.e. thyme, tarragon, rosemary, parsley, etc.
Salt and pepper to taste
Optional: 1 egg, beaten

1. Heat oven to 400ºF.
2. Melt butter in a large skillet over medium heat and add the onion, carrots, and celery; cook for about 5 minutes.
3. Sprinkle flour over mixture and stir. Cook for a couple of minutes, stirring occasionally.
4. Pour in broth, stirring constantly. Stir in the turkey and peas.
5. Bring to a simmer and cook for about 5 minutes. Stir in the cream and season with herbs, salt and pepper.
6. Pour mixture into a casserole dish or deep pie pan.
7. Roll out crust to about 1 inch larger than the dish you’re using.
8. Place the crust on top of the pot pie mixture; fold under and press crust onto the edge of the dish. Poke vents in the top of the crust. Brush the top with beaten egg.
9. Bake for 40 minutes or until golden brown and bubbly. Let cool for 5 minutes before serving.