2tablespoonscornstarch, + 3 tablespoons of water for a slurry
Instructions
Prep:
Preheat the oven to 425F (220C) and position the top oven rack in the middle of the oven. Thaw the frozen mixed vegetables, either in the microwave or under lukewarm water. Thawing them first avoids a runny pie filling from excess moisture. In a small dish, make a thick slurry by mixing the corn starch and water, and set it aside.
Make the filling:
Heat a large pan over medium-high heat. Once hot, add the oil and spread it around the pan. Add the chopped onions and celery, and sauté them for 3 to 5 minutes, until softened. Add all the seasonings and stir to toast them for about a minute.
Add the mixed vegetables, cooked chicken pieces, and chicken stock to the pan. Stir and cook everything for about 5 minutes. The liquid should come to a simmer or close to it. Add the milk, reduce the heat to medium-low, and let the liquid come to a slow simmer.
Add the slurry to the pan and mix it well with the liquid. Continue to let it simmer in the mixture for 3 minutes, then turn off the heat.
Assemble:
Place a 9-inch pie plate on a baking sheet to make it easier to remove from the oven. Remove the refrigerated pie crusts from the fridge and roll one out directly over the pie plate.
Use a ladle or large serving spoon to transfer the filling from the pot into the prepared pie dish. Roll the second pie dough out of the plastic and place it on top of the pie dish. Then, use your fingertips to seal the edges. With a sharp knife, make a cross-shaped opening at the center of the pie, then brush some milk over the top of the crust. The slits let the steam vent out, so the top isn't soggy, and the milk gives it a golden color.
Protect the pie's edges by folding a couple of foil strips into a 3-inch-wide strip and wrapping them around the edges. This prevents them from burning/browning too quickly and can be removed in the last 5 minutes of baking.
Bake:
Bake it in a preheated oven for 25 to 30 minutes, until the top of the pie crust is golden brown.
Take it out of the oven and let the chicken pot pie rest for 10 minutes before serving. This is a crucial step in letting the filling set.
Notes
Tip: Soggy bottoms usually happen when the pie filling leaks through a crack or tear in the bottom crust. Keep the dough refrigerated until the last minute, right before assembly, so it stays moist and rolls out easily. If it sits on the counter a long time, it can dry out and crack when you roll it out of the packaging.