Preheat the oven to 375 degrees F. Line a half sheet pan with parchment paper. Set aside.
In a large cast iron skillet over medium heat. Heat the oil and butter. Add the onions, carrots, and celery. Stir occasion and cook until softened, about 4 to 5 minutes.
Sprinkle the flour over the cooked vegetables and stir to combine. Cook about 1 minute, stirring continuously.
Gradually add the chicken broth and heavy cream. Stir frequently until mixture begins to thicken. Remove from the heat and add the frozen vegetables. Season with black pepper. Add the chopped rosemary. (Add more chicken stock if needed)
Assembling Chicken Pot Pie
On a lightly floured work surface, roll out the pie crust into a circle. Place in the bottom of a greased cast iron skillet (10-12-inches) or into a glass pie plate.
Add the shredded chicken to the unbaked pie shell.
Spoon the chicken pot pie ingredients into your prepared pie shell.
On a lightly floured work surface, roll out the top pie crust and carefully place over the pot pie. Gently roll under the edges and press down. Use a sharp knife to cut several vents into the top of the pot pie.
Brush the pot pie with an egg wash* using a pastry brush.
Place the cast iron skillet or pie plate on the prepared half sheet pan.
Bake in the preheated oven for 30-35 minutes. Or until the crust is golden and the filling bubbling.
Let cool 10-15 minutes before serving.
Video
Notes
For the chicken:
Place the chicken, one breast at a time inside a large zip-style bag. Keep the bag open so air can escape. Flatten the chicken with a rolling pin or a meat tenderizer.Season the chicken breasts with salt, black pepper, garlic powder, onion powder, and mustard powder (season to taste). Cook in a large cast iron skillet over medium heat, browning both sides. Finish in a preheated oven on a 375 degrees F for 15 to 20 minutes, or until thoroughly cooked. Let cool before shredding.You can also use store-bought rotisserie chicken in this recipe.Chicken Broth:I prefer to use Better Than Bouillon. Follow the directions on the jar.Be careful with adding salt to this recipe! Chicken broth already has lots of salt!*Egg Wash:1 large egg, 1 teaspoon water, pinch of salt (beaten together with a fork)Substitutions:You can add lima beans, or any frozen vegetable you prefer.