Dutch Oven Chicken Pot Pie

1/2 c butter
1/3 c all purpose flour
1/3 c. chopped onions
salt and pepper to taste
1 3/4 c chicken broth
2/3 c. milk
16 oz frozen vegetables ( any combo of corn, green beans, carrots and peas)
2 cups cut up cooked chicken
already-made pie crust for a 2 pie crust

preheat oven to 425 degrees. Over low heat, melt the butter in a saucepan. add the flour, onion, and salt and pepper. cook until the mixture is smooth and bubbly (is very thick), for about 3-5 minutes. remove from heat. Slowly add broth and milk to the flour mixture, stirring constantly to avoid lumps.
Return to the burner, turn the heat to medium high, and heat to boiling, stirring constantly until the mixture begins to thicken and fat bubbles roll to the surface. Boil and stir for a couple minutes more. Remove from heat and mix in frozen vegetables and chicken.  Line the bottom of a 10 inch dutch oven or chicken fryer with one pie crust. Sprinkle flour on the crust to cover lightly. Pour the chicken mixture into the crust. Top with the second pie crust, dust with flour, and crimp edges. Cut slits in the top.  Place the pie in the center of the oven and back for 45 minutes or until the crust is golden and the insides bubbling.