Make the pie dough. Get a small bowl of ice water ready so that it's nice and cold when you need it.
In a large bowl, whisk together 2 and 1/2 cups flour* (measured correctly; see note), 2 tablespoons sugar (1 tablespoon for savory pies), and 1 teaspoon kosher salt.
Add 1/2 cup butter-flavored shortening or fat of your choice. You can use lard or butter for this step if you want.
Chop up 12 tablespoons (1 and 1/2 sticks) cold butter into chunks. Add the butter to the bowl.
Use a pastry cutter to cut the butter and shortening into the flour, pressing down firmly with the pastry cutter. Scrape out the pastry cutter with a butter knife and continue until the flour is mostly incorporated, but don't go overboard. There should be pea-sized bits of butter or even bigger chunks are okay. Various sizes of butter is what you are looking for. See photos!
Crack an egg in a small bowl and whisk it together until it's a little frothy. Poor half of it into another small bowl, leaving about 2 tablespoons. (Save the other half of the beaten egg for brushing the finished pie.)
Add 1/4 cup ice water to 2 tablespoons beaten egg. Beat it together.
Add the mixture to the bowl with the flour. Use a rubber spatula to mix it together, hydrating the flour as much as you can.
Cover your hands with flour. Use your hands to knead the dough right in the bowl. Press the dough together and keep gathering up the dry bits to incorporate it into the mass. If the dough is not coming together, add ice water sparingly, 1-3 teaspoons at a time to moisten it. (I hardly ever add more water, but this does depend on climate.) Use extra water sparingly, you don't want to make your dough too wet. Stop kneading the moment that it has come together and is able to be shaped into a ball. Over working your dough results in a tough pie crust.
Use a knife or your hands to divide the dough in half. Use your hands to shape each half into a disc. Cover or wrap in plastic, and chill for at least 30 minutes.
Roll out the pie dough. Dust a work surface with plenty of flour. I love to use my pastry cloth for rolling out dough. (Another trick is to roll out the dough on a square of parchment paper; then you can invert the dough directly into the pie pan instead of having to lift the fragile dough.) Get out one of the discs of pie dough, leaving the other one to keep chilling.
Let the dough sit on the floured surface for 5 minutes or so, to warm up a bit.
Dust the pie dough with flour. Use your rolling pin to gently press the dough in the center, rolling outward. Rotate the rolling pin a quarter turn and gently press outward again. Check for cracks on the edges, and use your hands to press them and heal them a bit, adding a drop of ice water if necessary.
Dust with flour and continue rolling, rotating a quarter turn every time. Dust with flour again, and before it gets too large, lift the dough and turn it over (you can do this multiple times), dusting your surface with flour as you go. This is to make sure the pie dough is not sticking to your work surface. Continue dusting, rotating, and rolling.
Take the time to press together cracks at the edges, moistening with a drop of water and then dusting with flour as necessary. Continue rolling until the pie dough is about 13 inches across, making sure that it is not sticking on the bottom.
Place your rolling pin along the edge of the pie dough. Lift the edge of the pie dough and place it on top of the rolling pin. Roll the dough onto the rolling pin and carefully transfer it to a 9 inch pie plate. See photos. (If you rolled out your dough on parchment paper, you can invert the pie dough into the pie plate.)
Gently press the dough into the corners of the pie plate, fixing any cracks or tears as you go. There should be an overhang of dough along the edge. Leave it as is for a double crust pie.
If you are baking a single pie crust, fold the overhang underneath itself and flute the edges using your knuckles or fingers (see photos). If you are baking the crust before filling, follow this tutorial on How to Blind Bake a Pie Crust.
Place your pie plate in the fridge while you roll out the second pie disc. Roll the dough out to about 11-12 inches, a little smaller than the first one.
Fill your pie. Don't forget to dot with butter if your recipe calls for it. I always forget to do that!
Follow this tutorial for How to Lattice a Pie Crust if you want. It's so pretty!
For a traditional double crust, roll out the second pie crust, wrap it onto the rolling pin, and transfer to the top of your filled pie.
Now you should have two pie crusts overhanging the edge of your pie pan. Use your fingers to gently press the dough together on the edges. Fold both crusts underneath themselves so they are nicely lined up with the edge of the pie pan.
Use your thumbs or knuckles to flute the pie crust however you like. See photos.
Chill your pie in the fridge for another 30 minutes if the dough has gotten soft.
Just before putting your pie in the oven, remember to brush with milk or egg. I like to beat together 1 tablespoon beaten egg with 1 tablespoon milk. Sprinkle your pie with granulated or raw sugar, if it is a sweet pie.
Follow your pie recipe for instructions on how to bake. I like to bake my pies at a high temperature (425 degrees F) for about 15-20 minutes, them lower the temperature to 350 and bake for another 25-50 minutes. I always bake my pies on a baking sheet that has been preheated in the oven, to help bake the bottom of the crust and make it super flaky.
Don't forget to use a tin foil pie shield to cover your crust for the last half of the bake time. See photos. This will keep your crust from burning.
I know it's difficult, but for most sweet pies (especially fruit pies), it's important to let your pie cool to room temperature (2-4 hours) before cutting into them, so that the juices have a chance to set up.