Preheat your oven to 200°C (390°F) and gather all your ingredients.
Melt butter in a large skillet over medium heat until it sizzles and releases a nutty aroma.
Add chopped onions, carrots, and celery to the skillet. Cook, stirring occasionally, until the vegetables soften and become fragrant, about 8 minutes. They should look slightly translucent and tender.
Stir in shredded chicken and pour in the chicken broth. Let everything simmer gently until the mixture thickens slightly and the vegetables are fully cooked, about 10 minutes. You’ll see it bubbling and the filling becoming creamy.
Pour the filling into a deep-dish pie plate, spreading it out evenly.
Unroll your pie crust and lay it over the filling, trimming the edges as needed. Use a fork to seal the edges and create a decorative border.
Cut a few small slits in the top crust to vent steam and prevent bursting. Brush the crust with beaten egg for a shiny, golden finish.
Place the pie in the preheated oven and bake until the crust is golden brown and flaky, about 30-35 minutes. You’ll hear a satisfying crunch and see a beautiful, golden surface.
Remove the pie from the oven and let it rest for about 10 minutes. This helps the filling set and makes slicing easier.
Slice the pie and serve hot, enjoying the crispy crust and savory filling that bubbles at the edges. Perfect for a cozy, spooky dinner or comforting weekend meal.