1 1/3 c. frozen peas and carrots
1 c. diced potatoes (cook them partially or used canned)
2/3 C. butter
2/3 c. flour
2/3 c. chopped onion
1 tsp. salt
1/2 tsp. pepper
3 1/2 c. chicken broth (2 cans)
1 1/3 c. milk
6 c. cooked, cubed chicken (I never measure- just whatever looks good)
Rinse frozen peas and carrots under running water to separate.  Drain  and set aside.  Heat butter on low until melted.Stir in onions,  flour,  salt, and pepper.  Cook stirring constantly until mixture is bubbly.   Remove from heat.  Stir in broth and milk.  Heat to a boil, stirring  constantly.  Boil and stir for 1 minute.  Stir in chicken and  vegetables.  
Pour into a 9x13 pan ( I use a glass pyrex).   Place 2 refrigerator pie crusts over the top (the kind you find rolled up by the refrigerator rolls and pizza crust).  You have to trim them  because they come round and you are putting them on a square pan.  It  won't look to beautiful- but it makes up for it in taste!  Bake at 425 until the crust turns golden brown.