• Whisk together flour, cornstarch, salt in a large mixing bow. Add the leaf lard by the tablespoonful and butter cubes.
• Cut the fats in the flour using dough scrapers or a pastry blender until you get coarse crumbs. When you press the a small portion of mixture together with your fingers, it should hold the shape without falling apart.
• Crack an egg in a glass measuring cup (2 cup, about 480 ml, size), and add vinegar. Pour cold water to measure the liquid to reach 2/3 cup (158 ml) amount. Beat the mixture well.
• Drizzle about 1/2 cup (120 ml) of liquid around the crumb mixture and stir gently with a fork. Add a small amount of liquid on the dry spots and continue stirring until the mixture is slightly moistened. You may not need to use all of the liquid - use just enough to moisten the mixture slightly. Some crumbs are okay.

• When the dough mixture is moistened without being too sticky or dry, dump it on a lightly floured surface. Gather up the dough. Divide the dough in half. (If I am making a double crust pie, I usually make the bottom crust dough to be slightly larger than the top crust portion)
• Form each dough half into a disk and wrap with a piece of plastic wrap. Chill the dough for at least 1 hour before you roll out.

Rolling out and fluting pie crust

• Whack the pie dough with a rolling pin a few times if the dough seems too hard. Dust the surface with a little flour and start rolling the dough from the center out and rotating a quarter turn. Run your fingers under the dough to loosen it. Dust more flour if the dough feels sticking to the surface, but use as little as possible.
• Roll out into a circle until you get about 13-inches (33 cm) in diameter. This will fit to a standard 9 or 9 1/2 inch (23 cm) pie pan.
• Transfer the pastry to fit into a pan, gently nudging it down the sides of the pan. Lift up the overhanging dough and fold it under. Create the flute by using your thumb and forefinger to make a V pattern. Cover the pie shell with plastic wrap and refrigerate until ready to use.