Ingredients:
Biscuit topping:
2 cups all-purpose flour
1 tablespoon baking powder
1 teaspoon salt
3 tablespoons vegetable shortening or butter
1 cup milk
Extra 2 tablespoons milk for brushing

Filling:
2 tablespoons olive oil
1 medium onion, chopped
3 medium carrots, peeled and sliced
2 celery stalks, sliced
1 cup frozen peas
1 1/2 pounds boneless, skinless chicken breasts, cooked

4 tablespoons butter
4 tablespoons all-purpose flour
1 cup milk
2 cups chicken broth
1 teaspoon fresh thyme, chopped or 1/2 teaspoon dried
3 tablespoons fresh parsley, chopped

Directions:

1. Prepare biscuit topping: Put the flour, baking powder and salt in a large mixing bowl.  Add the chilled
   butter or shortening and rub into the flour with finger tips until the mixture resembles breadcrumbs.
   (The food processor may be used instead).
2. Sprinkle the mixture with the water and mix together with a spatula, until the dough sticks together. 
   Press the dough into a ball, then flatten into a 4 inch disc.  Wrap in plastic and set aside in refrigerator.
3. Preheat oven to 400 degrees Fahrenheit.
4. Prepare filling: In a medium  pan, heat the oil over medium heat.  Add the onion, carrots and celery;
   sauté about 2 minutes. Add the peas and one cup chicken broth and cook covered until tender.
5. Cut or shred the cooked chicken into bite sized pieces, then add to the cooked vegetables.
   Set aside in a medium bowl.
6. Heat butter over medium heat in the same pan.  Add the flour and cook for 1 minute.  Whisk in the
   remaining chicken broth, milk and thyme.  Bring to the simmer, then continue to simmer until sauce fully thickens, about 1 minute.  Season to taste with salt and pepper.
7. Pour the sauce over chicken, vegetable mixture and stir.  Add the chopped parsley.
8. Pour the mixture into a 13 x 9 inch shallow baking dish or individual pie dishes.  Cover with rolled out pie crust and brush with remaining milk.  Bake until golden brown and the filling is bubbly - 30 minutes for
   large and 15 to 20 minutes for individual.
9. Cool for 5 - 10 minutes before serving.