In a saucepan, combine chicken, carrots, peas, and celery. Add water to cover and boil for 15 minutes. Remove from heat, drain and set aside.
In the saucepan over medium heat, cook onions in butter until soft and translucent. Stir in flour, salt, pepper and celery seed. Slowly stir in chicken broth and milk. simmer over medium-low heat until thick. Remove from heat and set aside.
Place to chicken mixture in a bottom pie crust. Pour hot liquid mixture over. Cover with top crust, seal edges and cut away excess dough. make several small slits in the stop to allow steam to escape.
Bake in the preheated oven for 30 minutes or until pastry is golden brown and filling is bubbly. Cool for 10 minutes before serving.
Recipe by Sports Mom Survival Guide at https://www.sportsmomsurvivalguide.com/chicken-pot-pie/