Prepare the Filling

1. Sauté the Vegetables: In a large skillet, heat olive oil over medium heat. Add onions, carrots, celery, and garlic. Sauté until the vegetables are tender, about 5-7 minutes.
2. Add Turkey and Peas: Stir in the cooked turkey, frozen peas, parsley, thyme, salt, and pepper. Mix well to combine.
3. Create the Gravy: Pour in the broth and heavy cream. Bring to a simmer and let cook for 5 minutes. If you’d like a thicker filling, mix cornstarch with a little water and stir it in, cooking until thickened.
4. Cool: Remove from heat and let the filling cool slightly while you prepare the crust.

Assemble the Pie

1. Preheat Oven: Preheat your oven to 425°F (220°C).
2. Prepare the Bottom Crust: Roll out one pie crust and fit it into a 9-inch pie dish, trimming any excess overhang.
3. Add the Filling: Pour the turkey filling into the crust, spreading it evenly.
4. Create the Lattice Top: Roll out the second pie crust and cut it into strips. Lay half of the strips horizontally across the filling, then weave the remaining strips vertically to create a lattice pattern. Trim and crimp the edges of the crust to seal.
5. Apply Egg Wash: Brush the lattice top with the beaten egg for a golden finish.

Bake the Pie

1. Bake: Place the pie in the preheated oven and bake for 30-40 minutes, or until the crust is golden brown and the filling is bubbly. If the edges brown too quickly, cover them with foil.
2. Cool: Remove from the oven and let cool for at least 10 minutes before slicing and serving.