We love pot pies but can't stand the rubbery things at the store. This is a favorite at our house, perfect for cold days. I'll often make a double batch and freeze the second one in individual pie pans, ready to be baked another day.
Pre heat oven to 450. Roll out pie crust and place in deep dish pie pan. Prick all over with fork and bake until almost brown, 8-12 minutes.
If using raw chicken place oil in skillet on medium heat. Trim and evenly chop chicken. Season with 1/2 tablespoon garlic salt and 1/2 tablespoon herbs de Provence. Cook until just done, about 6 minutes. If using leftover chicken season. Set aside when done. Clean skillet for rou.
While chicken is cooking melt 2 tablespoons butter in medium pot. Dice onions and celery and place in pot, along with the remaining garlic salt and herbs de Provence. Dice carrots and add to pot when onion is soft. Skin and dice potatoes.
When potatoes are prepped add them to the pot, along with broth and enough wine to cover potatoes. Bring to boil, then reduce to medium low and cook, covered, for about 15 min or potatoes are just done.
Make rou while potatoes are cooking. Melt remaining butter in skillet and slowly whisk in flour. Cook for about 3 minutes, no need to brown. Remove from heat and whisk in milk. When milk is incorporated return to heat, cooking for 1 more minute.
Remove pot from heat and whisk in rou. Add chicken, and place in pie pan. Place crust on top, sealing edges. Cut vents and pace in 425 oven for 10 minutes. Reduce heat to 375 and cook for 20 more minutes, or until crust is browned. Gravy will thicken with standing, but we usually dig right in.