Heat oven to 425°F. Make pie crusts as directed on box for Two-Crust Pie, using 9-inch glass pie plate.
In 2-quart saucepan, melt butter over medium heat. Add onion; cook 2 minutes, stirring frequently, until tender. Stir in flour, salt and pepper until well blended. Gradually stir in broth and milk, cooking and stirring until bubbly and thickened.
Stir in turkey and mixed vegetables. Remove from heat. Spoon into crust-lined pie plate. Top with second crust; seal edge and flute. Cut slits in several places in top crust.
Bake 30 to 40 minutes or until crust is golden brown. During last 15 to 20 minutes of baking, cover edge of crust with strips of foil to prevent excessive browning. Let stand 5 minutes before serving.