In a 2 quart saucepan, melt butter over medium heat. Stir in flour, onion, salt and pepper. Cook, stirring constantly, until mixture is bubbly; remove from heat. Stir in broth and milk. Heat to boiling,stirring constantly. Boil and stir for 1 minute. Stir in chicken and peas and carrots; remove from heat.
Heat oven to 425 degrees F. Roll 1 pie crust and ease into an ungreased deep dish pie pan. Pour chicken mixture into crust-lined dish. Roll remaining pie crust and gently place over chicken mixture. Arrange cutouts on top crust. Turn edges of pie crust under; flute edge.
Bake for about 35 minutes or until golden brown.