• Preheat oven to 425* F.
• Chopthe carrots and celery. Boil in water for 15 minutes, then add the peas and chicken and boil one more minute. Drain.
• While the vegetables are boiling, finely chop the onions and make the gravy. Saute onion and minced garlic in the butter over medium heat until the onions are translucent, about 5 minutes. Add the flour and whisk until well mixed. Add the chicken broth slowly, one cup at a time. It'll look weird at first, but just keep whisking and it will come together and smooth out. See photos above for a great visual. Add the milk and whisk until smooth. Add the salt, pepper, celery seed and parsley. Simmer until thick, anywhere from 3-8 minutes. Set aside.

To assemble:

• Press pie crust into bottom of a pie pan. Put about half of the chicken and vegetable mixture into the bottom, then pour about half of the gravy over top. Repeat. If your pie plate is smaller, it will be a raised pie- don't worry about it. Place the top of the pie crust on top and seal to the bottom crust all the way around. Score the top of the pie with four 2-inch long cuts for venting.
• Cover the edges of the crust in foil so they don't get too dark.
• Bake at 425* for 25 minutes then pull off foil. Then bake an additional 5-10 minutes until a deep golden brown.
• Allow to cool 10-30 minutes before serving.