Prepare pastry crust and allow to chill before starting the pot pie filling. To create a single top crust with decorative cutouts, lightly dust the counter with oat flour or arrowroot (see notes for instructions for 2 crust method). Place a 3/4 of the dough on the counter and sprinkle with a little flour or arrowroot. Roll the dough out to 1/4-inch thickness, large enough to cover the inside edge of the baking dish. (If not using cutouts, roll dough to leave it wider than the baking dish by 1/2-inch to have enough to crimp the edges.) Slide a dough scraper or offset spatula under the dough to release it from the counter and lift it onto a parchment-lined rimmed baking sheet. Refrigerate until ready to top the pot pie. Roll out the remaining crust in the same way to create decorative cutouts to accent the top of the pie. Transfer these pieces to the fridge with the top crust. (Use any leftover scraps to create cinnamon-sugar baked treats -- see note in blog post.)
Heat oven to 425°F. Prep vegetables and rinse peas to separate and defrost. Melt 1/4 cup butter over medium heat in a deep skillet. Stir in 3/4 cup onion, 1 cup carrots, 3/4 cup celery, and 1/2 teaspoon thyme and cook until vegetables are softened, about 5 minutes. Season with 1/2 teaspoon salt and 1/2 teaspoon pepper. Stir in 2 cloves minced garlic and cook until fragrant, about 2 minutes. While vegetables are cooking, prepare baking pan with a thin coating of butter. Sprinkle rice flour over the vegetables and stir in.
Stir in 2 tablespoons cognac and allow to evaporate for 30 seconds, then whisk in 2/3 cup cream, 1 3/4 cups stock, and 1 to 2 teaspoons Worcestershire (add 1 teaspoon, then taste before adding another). Simmer for 4-6 minutes or until carrots are just tender, stirring occasionally as the sauce thickens. Stir in 3 cups turkey and 3/4 cup peas and allow to warm through. Taste and season with additional salt and pepper, if needed.
Pour filling into greased baking pan. Cover with the top crust and arrange any cut-outs or decorative pieces on top. Pierce crust with a sharp knife in several places to allow steam to vent while baking. Brush crust with 2 tablespoons cream just before baking.
Bake at 425°F for 20-25 minutes until golden brown and bubbly. Remove dish from oven and let stand for 5 minutes before serving.
Double Crust Pie Instructions:
Roll out 2/3 of the crust 1/4-inch thick between 2 sheets of parchment as described in Step #1. The crust should come up the sides, but doesn't have to be perfect as the filling and top crust will cover it.
Pierce the bottom crust with a fork and bake at 350°F for 15-20 minutes while cooking the filling. Pre-baking the bottom crust will help keep it from getting soggy from the filling. Read more here about tips and tricks for pre-baking pie crusts: https://www.seriouseats.com/2016/10/how-to-blind-bake-a-pie-crust.html
Continue with Step #1 in rolling out the top crust.
Skip the bottom crust and embellish the top -- The posted recipe includes ingredients for a double-crust so there is plenty of pastry dough to create embellished accents or sprinkle with cinnamon and sugar for a special treat.
Make ahead -- Each component can be prepped ahead up to 5 days (or frozen) before the final assembly. The assembled pie can be reserved and refrigerated for up to 3 days before baking. If storing more than 24 hours, store pastry crust separately and place just before baking. Baking time will take a little longer when starting with a cold pie, so allow 40-45 minutes bake time. If crust begins to brown too quickly, simply cover with foil until the filling starts to bubble.
How to reheat pot pie -- Reheating individual portions in a microwave for 2-3 minutes, but the pastry crust will suffer. To reheat and retain the best texture, place individual portions in a 350°F oven for about 10 minutes to gently reheat and finish under the broiler for a minute to crisp the crust, if needed.
How to freeze pot pie -- The entire pie can be frozen before baking. However, doing so will require longer baking time and may result in a soggier pie crust. I recommend freezing the filling and the pie crust separately. Freeze the filling in a zip-type freezer bag, with as much air removed as possible, pressed flat (this will help it thaw quickly). Roll out the pastry crust to the size needed. Refrigerate to stiffen, then double wrap in plastic wrap. Place in the freezer on a flat surface as much as possible.
How to prepare pot pie after freezing -- Defrost filling and pastry crust in the refrigerator up to 3 days before baking. When ready to bake, pour filling into a prepared casserole dish and top with crust. Bake at 425°F for 30 minutes, until hot and bubbly and crust is golden brown.