Step 1

For the Crust: Prepare a double batch of Flaky, Tender, and Nutty Whole Wheat Pie Crust as directed. Divide dough in half and roll each half into a thin sheet, around 3/16 inch thick, using as much flour as needed to prevent sticking along the way. Transfer pieces to a half sheet pan, cover tightly with foil, and refrigerate at least 2 hours and up to 48 hours before using.

Step 2

For the Chicken: Combine chicken stock, chicken parts, onion, carrots, celery, garlic, thyme, parsley, rosemary, and bay leaf in a 5-quart stainless steel pot or saucier. Cover and place over medium-high heat until stock registers about 150°F (66°C) on a digital thermometer.

Step 3

Adjust heat to maintain that temperature, plus or minus 10°F, and cook until thickest part of chicken registers 135°F (57°C), about 1 hour. Remove chicken with tongs, set aside on a rimmed platter, and cover loosely. Strain stock through a mesh sieve into a large bowl, discard solids, and set stock aside to cool.

Step 4

For the Filling: Combine gelatin and 1/4 cup (55ml) cooled stock in a small bowl and whisk until no lumps remain; set aside. In a 5-quart saucier, melt butter over medium-low heat, then whisk in flour. Stir with a heat-resistant spatula until roux is fragrant and a nutty blond color, about 5 minutes (it's okay to adjust the heat if this seems to be happening too slowly). Stir in diced onion, carrots, and celery and continue cooking and stirring until vegetables are slightly softened, about 7 minutes more.

Step 5

Add white wine and 1 quart reserved stock, stirring constantly until smooth; remaining stock from poaching can be reserved for another use. Increase heat to medium-high and bring to a boil, stirring constantly. Once it begins to bubble, remove from heat. Stir in frozen peas, diced pimentos, and prepared gelatin, followed by salt, thyme, pepper, and Worcestershire sauce. Stir until gelatin has fully melted into sauce and adjust seasonings to taste.

Step 6

Shred or dice reserved chicken, discarding skin and bones, then stir into filling. Transfer to a large but shallow container, such as a 9- by 13-inch baking dish, to increase the surface area and speed cooling. Refrigerate, uncovered, stirring from time to time, until no warmer than 50°F (10°C), about 1 hour. If it better suits your schedule, the filling can be covered and refrigerated up to 3 days, or frozen in an airtight container for 3 months.

Step 7

To Assemble: Adjust oven rack to middle position and preheat oven to 400°F (200°C). With a sharp knife, cut 1 sheet of chilled dough into 6 roughly equal squares. Nestle each one into the bottom of a 2-cup-capacity oven-safe dish. Cut 6 "lids" from remaining sheet of pastry with a sharp knife, using an overturned 2-cup baking dish as your guide; alternatively, cut with an appropriately large cookie cutter. Set pastry lids aside and use scraps to patch gaps in coverage along the bottom crusts, all the way to the top edge of each dish.

Step 8

Divide filling evenly between dishes, about 1 1/2 cups each (12 ounces; 340g), although the exact amount will vary with the specific amount of vegetables and chicken used. Top each dish with a pastry lid and gently crimp the edges with a fork to seal pastry to bottom crust.

Step 9

For the Egg Wash (if using): Whisk egg, cream, and salt in a small bowl. Brush over top crust of each pie in a thin, even layer. This will give the crust a glossy golden sheen.

Step 10

Transfer dishes to a foil- or parchment-lined baking sheet and bake until pastry is golden brown and filling is bubbling-hot, about 1 hour 15 minutes. Let cool at least 30 minutes before serving, to allow the filling to thicken and reach a safe temperature to enjoy. Covered in foil, leftovers can be refrigerated up to 3 days and reheated to serve.