1 ½cups(about 283 to 340g)peeled and chopped (1/4-inch) potatoes
½teaspoonsalt
¼teaspooncoarsely ground black pepper
5tablespoonsbutter
½cup(71g)all-purpose flour
3cupslow-sodium chicken broth or stock
2cups2% or whole milk
3cups(about 340 to 454g)cooked, diced chicken
¾cup(85 to 113g)frozen peas
Biscuit Topping:
2 ½cups(284g)all-purpose flour
¾teaspoonbaking soda
4teaspoonsbaking powder
1teaspoonsalt
11tablespoons(113g)salted butter, cut into pieces and well-chilled
1 ¼cupsbuttermilk
Pie Crust Topping:
One 9-inchdouble crust recipe (see note)
Instructions
Preheat the oven to 400 degrees F. Lightly grease a glass or ceramic 9X13-inch baking pan. Alternately, you can use 10- or 12-ounce oven-safe ramekin dishes.
For the filling, in a 5- or 6-quart pan set over medium heat, add the olive oil, onions, celery, carrots, potatoes, salt and pepper. Cook for 1-2 minutes, stirring often. Cover the pot with a lid, reduce heat to medium-low, and continue to cook, until the vegetables are lightly steamed and mostly tender, 5 to 7 minutes (they'll cook more in a later step). Check every couple of minutes to make sure the vegetables aren't sticking to the bottom of the pan. Scrape the mixture to a plate or bowl.
Return the pot to medium heat. Add the butter and cook until melted. Stir in the flour and whisk to combine. Continue cooking, stirring constantly, for 1 to 2 minutes.
Gradually whisk in the broth and milk, adding 1/2 to 3/4 cup at a time and whisking it in completely before adding more.
Bring the mixture to a simmer, stirring constantly, and cook until the sauce has thickened, 5-7 minutes.
Stir in the chicken, frozen peas, and reserved vegetables and remove from the heat. Season to taste with additional salt and pepper, as needed!
Carefully ladle the pot pie filling into the prepared baking dish(es). Let the mixture cool until warm (this helps prevent the biscuits/pie crust from melting before it bakes - the topping will be more flaky and tender if the filling has cooled a bit). If you don't want to wait, quickly layer the biscuits or pie crust on top and get the dish into the oven as soon as possible.
For a pie crust topping, roll out the pie crust to fit on top of the baking dish with about a 1/4-inch overhang. Roll/lift the pie crust to fit evenly over the top of the pot pie filling - make sure it's resting directly on the filling and not hanging above suspended on the edges of the pan. Trim the edges to about 1/4-inch (if needed). Flute the edges or tuck them into the inside of the baking dish.
For a biscuit topping, make the biscuits by whisking together the flour, baking soda, baking powder, and salt. Cut in the butter until the butter pieces are about pea-size (or grate it in with the large holes of a box grater and toss with the flour). Add the buttermilk and mix until the dough forms a cohesive ball (don't over mix). Turn the mixture onto a lightly floured counter and press into a rough rectangle about 1/2-inch thick.
Gently fold the dough in thirds. Press or roll into a thick rectangle and repeat that process three or four more times (this creates the flaky layers in the biscuits). Press or roll the dough into a thin rectangle, about 1/4-inch thick.
Cut the rectangle into about 15 square or rectangle pieces. Place the biscuits evenly across the top of the pot pie with the edges just touching. You can place the dish on a foil-lined baking sheet to catch any spillover, if desired.
Bake the pot pie for 35 to 40 minutes until the pie crust or biscuits are golden and cooked through. Let the pot pie rest for 10 to 15 minutes before serving.
Notes
Pie plate: This amount of filling will likely fill two 9-inch pie plates for two pot pies. Pie crust: Use your favorite store bought or homemade pie crust recipe for a pie crust topping. You'll need a bit more pie crust than a standard 9-inch pie crust to top a 9X13-inch pan, so it's best to plan on using a double crust pie dough recipe to have enough to top the pan (or individual pot pies). UPDATE: I edited the recipe to include slightly more biscuit dough to more easily cover a 9X13-inch pan.