Crack egg into measuring cup; add vinegar and then enough water to make 7/8 of a cup, more or less. Use fork to whisk egg mixture together. Pour egg mixture into dry ingredients almost all at once. (I usually hold out about a quarter of a cup.) Mix with the fork, gently gathering the dough from the outside of the bowl. Add the rest of the liquid if necessary. Do not over mix. Alternatively, you can use a stand mixer or food processor - just be sure not to over mix.
2 teaspoons apple cider vinegar, Water, 1 large egg
As soon as the dough comes together, turn it out onto a floured surface. Use your hands to carefully press the dough together---you're not kneading here, just binding the ingredients together in a solid ball.
Refrigerate dough for 1 hour. I wrap mine in a damp kitchen towel.
Roll the dough
Divide dough evenly into two, then roll out on a liberally floured surface. The rolled pie crust should be big enough to extend past the edges of the pie plate by an inch or two.
Fold the dough in half for easy lifting, then move into a pie pan. Carefully press the dough into the bottom of the pan.
For a single crust pie like pumpkin or lemon merengue, tuck the dough edges under and then crimp all around.
For a filled pie, add a generous amount of filling, and top with the second crust. Roll both dough edges under at the rim of the pie pan, and crimp them together.
Bake as directed in your favorite recipe.
Notes
Crimping is an art! Perfect crimping takes years of practice.
This homemade pie crust recipe makes a double crust -- enough for a top and bottom. If you're making a single crust pie such as a pumpkin pie or lemon meringue, you'll be able to make two.
If you only need one of these, you can freeze the other for another pie another time.