Cook the Chicken: Boil or pan-sear chicken breasts/thighs, then dice into bite-sized pieces.
Prepare the Filling: In a large skillet, melt butter and sauté onions, carrots, and potatoes until slightly tender. Stir in flour to make a roux.
Make the Sauce: Gradually whisk in chicken broth and milk, stirring until thickened and creamy.
Combine: Add peas and cooked chicken. Season with salt and pepper.
Assemble: Pour the filling into a pie dish lined with one crust. Cover with the top crust, seal the edges, and cut small slits on top for steam.
Bake: Brush with egg wash and bake at 400°F (200°C) for 25–30 minutes, or until golden brown and bubbling.
