Here we have celery, onion, turnip, carrot and sweet potato roughly chopped to appx the same size. You can also use green peas, green beans, parsnips or whatever you have on hand. Put all veggies into a sauce pot along with 2 cups of stock on stovetop, and simmer gently while you do the rest of your prep. The head start here makes sure everything is cooked evenly when it goes into the pie.
A roux is a thickener for soups, stews, or liquid-based fillings. Melt the butter in a small saucepan, and then whisk in the flour to make a paste. Cook over low heat till it becomes so thick that it sticks to your whisk.
Remove from heat, whisk in the milk or stock and the thyme. Stir till thickened.
Once the veggies are pretty well cooked, stir tin the roux.
On the bottom layer of your pie or baking dish, add half the chicken or turkey.
Then, a thick layer of the veggies and roux.
Top with the rest of the chicken or turkey.
Remove the chilled dough from the fridge. Roll it out on the countertop till it’s thin.
Paint a little water around the rim of the pie dish, then plop the dough on top, like a fallen parachute.
Pinch around the sides of the edge of the pie pan, and then using a small sharp knife, slice around to remove the excess.
Slash the top a few times so the steam can escape, and pop it in the oven for about an hour, or until the crust is golden and the filling is bubbling.
If using mashed potatoes, spread into an even layer on top and bake about 45 minutes until bubbling, maybe the last few minutes under the broiler.