Preheat your oven to 400°F (200°C) and lightly grease individual pie dishes or one 9-inch pie dish.

In a large skillet, melt the butter over medium heat.

Add the chopped onion and sauté until it becomes translucent, about 3–4 minutes.

Toss in the diced carrots and potatoes, stirring occasionally, until they are just tender, approximately 8–10 minutes.

Sprinkle the flour over the vegetables and stir well for about a minute to cook off the raw flour taste.

Gradually whisk in the chicken broth, followed by the heavy cream. Bring this mixture to a gentle simmer, stirring until it thickens, around 3–5 minutes.

Stir in the cooked chicken, peas, thyme, garlic powder, and season with salt and pepper to taste. Simmer for an additional 1–2 minutes.

Roll out the puff pastry on a lightly floured surface if needed and cut circles to fit your pie dishes.

Spoon the filling into your prepared dishes, lay the pastry over, crimp the edges to seal, and cut a few slits for steam to escape.

Brush the pastry with the beaten egg for that enticing golden finish.

Bake for 25–30 minutes or until the pastry is beautifully golden. Allow to cool before serving.