1 cup chopped onion 1 cup chopped celery 1/3 cup butter or margarine 1/2 cup flour 2 cups chicken stock 1/2 teaspoon chicken bouillon granules -- to taste, optional 1 cup milk 3 cups diced cooked chicken 16 ounces frozen mixed vegetables (see note) 2 medium potatoes -- cut in 1/2" cube salt and pepper, to taste
Melt butter in a Dutch oven or deep skillet. Cook onion and celery until tender. Add flour and stir and cook for 1 minute. Add chicken stock and milk and stir until thickened and no flour lumps remain.
Stir in mixed vegetables and potato. Simmer, stirring often (the mixture is very thick and you don't want it to scorch), until the potatoes are barely done. Stir in chicken and season to taste.
Place mixture in freezer container and freeze.
Top with biscuits or puff pastry or pie crust. If you are using a pot pie filling that is cold from the fridge it's important to bake it uncovered first--or heat it in the microwave or on top of the stove before adding the topping.
If you put the topping on the cold filling, the topping will be soggy on the bottom and overcooked on the top before the filling is hot and bubbly.
I often bake my biscuits separately and just put them on top of the dish hot from the oven or poured hot into a serving dish--like a Corningware shallow baker with the freshly cooked hot biscuits placed on top.
NOTE: green beans, peas, corn, lima beans and carrots