Combine 2-1/2 C flour, 1 t salt and 2 sticks cold butter in food processor. Slowly add 1/2 C ice water until dough holds together. Flatten into two discs between plastic wrap. Chill for at least an hour.
Preheat oven to 425 degrees. Melt 1/3 C butter in saucepan then slowly whisk in 1/3 C flour. Add 1-1/2 C milk and 1-1/2 C water and simmer until thickened. Season with salt, pepper, parsley and thyme.
Roll out bottom crust and generously fill with cooked shredded chicken, 2 cooked sliced carrots, 1/2 can green beans, 1/2 cooked chopped onion and 1/2 can corn. Pour liquid over top and cover with top crust. Vent, brush with milk and bake 30-35 minutes until golden brown.
Disclaimer: I DO NOT advocate the eating of chickens (chickens are your friends, NOT food !) but this pot pie is just SO darn good !