If you just want a regular pie crust, no funny buttermilk-cornmeal business, just omit the cornmeal and sub in icy cold water for the buttermilk.
1 cup all-purpose flour
1/4 cup fine cornmeal
1/2 tablespoon granulated sugar
1/2 teaspoon salt
6 tablespoons unsalted butter, cut into 6 pieces
3 to 5 tablespoons buttermilk
2 tablespoons unsalted butter
1 medium onion, cut into 1/2-inch pieces
1 large carrot, peeled and thinly sliced
1 celery stalk, thinly sliced
1 small russet potato, unpeeled and cut into 1/2-inch pieces
1 pound boneless, skinless chicken breasts, cut into 1-inch pieces
5 tablespoons all-purpose flour
1-1/2 cups chicken stock
1 cup frozen peas
2 teaspoons chopped fresh thyme
1-1/2 teaspoons kosher salt
1/2 teaspoon freshly ground black pepper
2 tablespoons heavy cream
For the crust, add the flour, cornmeal, sugar, and salt to the bowl of a food processor and pulse to combine. Add the butter pieces and pulse in 1-second beats until you have chunks of butter the size of peas, 8 to 10 pulses. Add 3 tablespoons of buttermilk through the feed tube, and pulse until the dough starts to clump. If it doesn't clump after 12 pulses, add a little more buttermilk, pulsing the motor after each addition, until the mixture clumps together. (You can also cut the butter into the dry ingredients with an electric mixer, a pastry blender, or your fingers. Add the buttermilk in increments, fluffing with a fork, until the dough holds together when pressed.) Dump the dough onto the counter and form it into a ball. Flatten it into a disk about 3/4-inch thick and wrap it in plastic wrap. Let the dough rest in the refrigerator for 30 minutes.
For the filling, heat the butter in a large saucepan over medium-high heat until it foams. Add the onion and cook for 2 to 3 minutes, stirring occasionally, until it softens a bit. Add the carrot, celery, and potato and sauté, stirring, for 4 to 5 minutes until the vegetables start to soften. Add the chicken and continue to cook for another 2 to 3 minutes, stirring, until the chicken pieces start to turn opaque. Stir in the flour, mixing to coat all of the meat and vegetables, and cook 2 to 3 minutes longer. By this time, the filling will start to look a bit sludgy and a brown film should be forming on the bottom of the pan. Add the stock and bring to a simmer. Add the peas, thyme, salt, pepper, and cream and stir well. Simmer, scrapping up the browned bits clinging to the bottom of the pan, for about 5 minutes or until the filling thickens. Remove from the heat and spoon into a 9-inch pie plate or other similarly sized casserole dish.
Preheat the oven to 350°F. Roll out the dough on a well-floured surface into a circle about 1/4-inch thick and at least 10 inches in diameter. With a bench scraper or spatula, flip one side of the dough over the top of the rolling pin, gently loosening the dough if it sticks to the counter, until it is fully draped over the pin. Center the dough over the filling and unfurl. Gently tuck the edges of the dough down into the gap between the filling and the sides of the plate to enclose. Crimp the edges decoratively if you want or leave as is. Cut a few steam vents into the dough with a paring knife. Place the pie on a baking sheet to catch any overflow. Bake for 30 to 45 minutes on the top rack of the oven until the crust is golden brown and the filling is bubbly. Remove from the oven and let sit for 15 minutes before serving. Pie will keep for several days covered in the fridge. To reheat, I actually lift off the crust and heat it on a pan in the toaster oven and heat the filling separately in the microwave. Then I reassemble. That way, the crust is nice and crisp instead of soggy.
Source: Filling adapted from Flour, Too by Joanne Chang