Place the flour and salt in a large bowl and whisk to combine. Add the fat (lard, shortening, or butter) and mix with a pastry blender or two forks until pea-sized lumps form.
In a small bowl, whisk together the egg, vinegar, and cold water.
Add the liquid to the flour mixture and mix until a soft dough forms.
Divide the dough into two portions. Keep at room temperature or refrigerate until ready to roll out.
Place one portion on a floured work surface. Roll with a rolling pin, then turn 90°F and roll again. Continue, turning and rolling, until the dough is in a 12-inch circle.
Use as directed in a pie recipe.
Notes
I made this recipe with all lard and again with half lard/half butter. I preferred the half lard/half butter recipe slightly more. The butter adds a buttery flavor that lard lacks. Shortening works well in place of the lard. If the dough is too wet, add 1 tablespoon of flour at a time until the dough is no longer sticky. If the dough is too dry, add a sprinkle of water at a time until it comes together. Avoid over mixing the dough, which can make it tough. If you use all salted butter in place of the lard, reduce the salt in the recipe by half.Want a shiny pie crust? Whisk together one egg and one tablespoon of milk. Gently brush it over the top crust before it goes into the oven. You can also sprinkle turbinado sugar or sanding sugar over the egg wash if you'd like. Want a sweeter crust? Add 1 tablespoon of granulated sugar to the recipe.Make it ahead: wrap the dough disks tightly in plastic wrap and refrigerate for several days, or freeze for up to two months. Wrap the disks in foil and then slip into a freezer bag before freezing.