Prepare pie crust as directed on box and place into a 9" glass pie plate.
In a large saucepan, melt butter over medium heat. Add onion and cook for 2 minutes until tender.
Stir in flour, salt, and pepper until blended. Gradually stir broth and milk, cooking and stirring until bubbly and starting to thicken..
Stir in turkey and vegetables. Remove from heat.
Spoon Mixture into prepared pie plate.
Top with Second Crust, Flute, and Make slices to vent.
Fluting the double pie crust.
After you place the top pie crust on, trim the edges of both crusts evenly, leaving 1/2 " overlapping the pie plate. Fold the 2 crusts under 1/2". You can now do your decoration. To flute, just take your thumb and pointer finger of one hand and the pointer finger of the other hand, and pinch them together. If you don't want to flute you can take a fork and press down along the top after you have folded the crusts underneath. Make sure you vent pie crusts with a sharp knife by making 1" slits several places on top crust.
Place on a Cookie sheet in the center of the oven and bake for 40 minutes. Check 1/2 way through baking and place aluminum foil over crust if its over browning.
Notes
You can use your favorite homemade crust here as well.