Step 1

Preheat the oven to 425 degrees. Melt the butter in a large skillet, Dutch oven or frying pan set over a medium high heat.

Step 2

Stir in the onion, carrot and celery, along with a pinch of salt. Cook until the onions are soft and have started to color.

Step 3

Stir in the fresh thyme, followed by the chicken, seasoned well with salt and pepper. Cook until the chicken has started to brown. Sprinkle with the flour and cook for a further minute.

Step 4

Pour in the broth, and the heavy cream or milk. Cook, stirring often, until the sauce has thickened to slightly thinner than you want your finished pie filling. Stir in the frozen peas, and remove from the heat. Add a little more salt and pepper, if needed, and set aside to cool a little.

Step 5

While the filling is cooling, lightly butter a 9 inch pie plate and line with one of the pie crusts.

Step 6

Add the filling to the pie dish, and brush the exposed edges of the pastry with beaten egg. Lay the other pie crust on top, and press down to seal the edges. Trim off any excess with a sharp knife and crimp the edges.

Step 7

Brush the top of the pie with egg wash and cut a small slit in the middle to let out steam. Bake for 30-35 minutes, or until the pastry is cooked and the top is golden - you may need a little more or a little less baking time if your oven runs a little hot or a little cold.

Step 8

Let the pie to rest for 10-15 minutes before slicing.