½cupvegetable shortening(110g, or butter, if you'd like an all butter crust)
1stickcold unsalted butter(115g, diced)
½ to ⅔cupice water
Egg wash(1 egg beaten with 1 tablespoon water)
Preheat the oven to 350 degrees F. On a sheet pan, drizzle the chicken breasts with olive oil and sprinkle liberally with salt and black pepper.
Bake in the oven for 35-40 minutes. When the chicken breasts are done cooking, take them out of the oven to cool, and remove the meat from the bone, cutting the chicken into large chunks. You can save these bones for a small batch of stock or plan to cook the chicken further in advance so you can use the stock for the pot pie filling. If you decide to do the latter, simmer the bones in about 5 cups of water for a few hours.
While the chicken is cooking, prepare the pastry. Mix the flour, salt, and baking powder in the bowl of your food processor. Add the shortening and butter and pulse about 10 times, until the butter and shortening are the size of small peas.
With the food processor on, add the ice water--just enough for the dough to just come together. You may have to pause and give it a stir with your hands, as some portions of the dough will be wetter or dryer. Dump the dough onto a clean, floured surface and knead gently into a ball. No need to overwork the dough! Wrap it in plastic and transfer to the refrigerator to rest for 30 minutes.
Now, back to the filling. In a heavy-bottomed pot, heat 2 tablespoons of olive oil over medium-high heat. Add the garlic and onions, and cook until translucent. Next, add the carrots and cook for another 10-15 minutes, stirring occasionally. Next, add the bell pepper and cook for about 3 minutes.
Add the butter, stirring to help it melt, and allowing the vegetables to cook further. When the butter is completely melted, turn down the heat to low, and add in ¾ cup of flour. Stir the flour and vegetable mixture constantly for 2 minutes.
Add the chicken stock, stirring thoroughly and breaking up lumps. Turn the heat back up to medium-high, so the sauce thickens and bubbles. When the sauce has a gravy-like consistency, add the frozen peas and diced chicken breast, followed by the heavy cream, parsley, and thyme. Simmer for an additional 5 minutes, and remove from the heat.
Now, to assemble your pot pies! Preheat the oven to 375 degrees F. Choose your oven-safe vessels and fill with the chicken pot pie filling, leaving about an inch of clearance between the top line of the filling and the baking dish. I made one large casserole, and 3 smaller ones, so I cut my dough into 4 proportional pieces. No need for this to become an exact science! Roll the dough out on a clean, floured surface.
Lay the dough over the casserole dishes, and tuck any excess in at the rim to flute the edges. Brush the crust with egg wash, cut vents into the top, and place on a baking sheet. Bake the pot pie(s) for 1 hour, until bubbly.