Use a food processor to combine the flour, cold butter, and salt into a crumbly dough. Slowly add the water and pulse until a smooth dough forms. Chill until ready to roll out, or for about one hour.
Remove the meat from the cornish hen, then chop the vegetables and herbs. Melt the butter in a large skillet. Add the potatoes, onions, and carrots and sauté until softened. Then add the mushrooms, garlic, and zucchini.
Add the chicken broth to the skillet and let the volume of liquid reduce by half. Stir in the cornish hen meat and broccoli. If the filling has too much liquid, sprinkle about a tablespoon of flour over the filling to thicken it. Stir in the sage, marjoram, tarragon, and red pepper flakes.
Preheat the oven to 350°F. Roll out the pie crust to about a quarter of an inch thick. Butter and flour the inside of a pie pan or springform pan. If making stackable pies, use a smaller ramekin or pan for a second pie. Reserve enough of the pie crust to make decorations, as desired.
Line the inside of the pie pans with crust, then quickly pour in the filling. Cover the filling with a second layer of pie crust. Seal the edges of the crust together, then brush the tops with egg wash.
Bake for 35-45 minutes or until the tops of the pies have started turning golden brown. The tops should sound hollow when tapped in the center. Remove from the oven and cool.
Optional: Decorate the pies with remaining pie crust (examples: feathers, roses, a crown, etc). Brush with egg wash and then bake for an additional 15-25 minutes until the decorations have browned. Cool slightly.
Serve the pie warm or at room temperature. Cut with Valyrian steel. Enjoy!