In a medium sauce pan combine raw cubed chicken, carrots, peas and potatoes. Add just enough water to cover And a pinch of salt and pepper. Bring to a boil, reduce heat and simmer for 10 - 15 minutes, or until carrots and potatoes are just fork tender. When done drain in colander and set aside.

Preheat oven to 425°F. Grease a square 2 quart casserole dish all over with 2 tsp butter. Unroll one pie crust and press into dish, forming and pressing from center out to fit and stretch up sides of dish, almost to top edge. If you get any tears just pinch 'em back together. Set aside.

In same sauce pan used for chicken mix, melt butter over medium heat. When melted add onions and cook until translucent, Stirring frequently. About 3 minutes. Whisk in flour, salt, pepper, celery seed and thyme to make a roux. Cook until roux is golden, whisking frequently. About 2 minutes more.

Slowly add chicken broth and milk, whisking constantly to prevent clumping and sticking to bottom. Bring to a simmer until thickened, stirring constantly. About 5 minutes. Turn off heat. Gently fold chicken and veg mixture into sauce.

Pour filling into bottom pie crust, spreading out evenly. Unroll and add top crust, pinching to seal edges (use the tines of a fork for best seal). Cut a few slits for steam vents in top. Pop it in the oven and bake 30-35 minutes or until top is golden brown.

When done remove from oven, spread an additional tablespoon of butter over top to melt into crust if desired. Allow to cool 10 minutes, dish up and enjoy!