Start by measuring out all your ingredients. Make sure your vegetable shortening is cold and cubed for the best results.
In a large mixing bowl, whisk together the 4 cups of all-purpose flour, 1 tablespoon of granulated sugar, and 1 teaspoon of salt until well combined.
Using a pastry cutter or a fork, cut the 1 ½ cups of cubed vegetable shortening into the flour mixture. Continue until the mixture resembles coarse crumbs with pea-sized pieces.
In a separate bowl, whisk together the beaten egg, 1 tablespoon of vinegar, and ½ cup of water.
Pour the wet ingredients into the flour and shortening mixture. Stir gently with a fork until the dough starts to come together. Be careful not to overmix; you want to keep the dough flaky.
Divide the dough into two equal portions. Shape each portion into a disc, wrap in plastic wrap, and refrigerate for at least 30 minutes.
Once chilled, remove one disc of dough from the refrigerator. On a floured surface, roll out the dough to about 1/8-inch thick. Carefully transfer it to your pie dish, easing it into place without stretching.
Trim any excess dough hanging over the edges of the pie dish. Crimp the edges with your fingers or a fork to create a decorative border.
If your pie requires a top crust, repeat the rolling and transferring process with the second disc of dough.
Fill your pie with your chosen filling and bake according to your pie recipe's instructions.
