Process flour, sugar, and salt together in a food processor until combined, about 5 seconds.
Scatter shortening over top and process until mixture resembles coarse cornmeal, about 10 seconds.
Scatter butter in and pulse the mixture until it resembles coarse crumbs, about 15 pulses (To do this by hand, freeze the shortening and butter and grate it into the flour using a box grater, and rub the flour-coated pieces between your fingers until the flour turns pale yellow and coarse).
Sprinkle 6 tablespoons of ice water over the mixture and pulse until the mixture is evenly moistened and very crumbly (To do this by hand: Transfer mixture to a large bowl. Sprinkle 6 tablespoons of ice water over the mixture. Stir and press dough together, using a stiff rubber spatula, until dough sticks together. If the dough does not come together, stir in remaining ice water, 1 tablespoon at a time until it does).
Dump the crumbly dough out onto a clean work surface and divide it into two even piles. Use your hands to quickly knead the dough into a soft and malleable disk.
Wrap the dough disk tightly in plastic wrap, then refrigerate for at least 1 hour, or up to 3 days, until ready to roll out and use.
Notes
This recipe makes a double crust. If you only need a single crust, you can either change the servings to 1 or save the 2nd disk of dough for another time.
Keep everything well chilled! In order to prevent shrinking and losing flakiness, it’s important to keep all of your ingredients as cold as possible when making pie crust. so be sure to use ice water and well-chilled butter.
Don’t overwork the dough. It’s important to avoid (over-mixing or overworking the dough, especially when you are adding the water, forming the disk, and rolling it.
Don’t skip resting the dough. This is an essential step. The gluten in the dough needs time to rest in between steps. This will help the pie crust from shrinking when baked.
Avoid stretching the dough. Let the dough naturally fall into the bottom of the pie pan so that it is not stretched out. Stretching can cause the dough to shrink during baking. When rolling out and transferring the dough into a pie pan, try to avoid pulling or stretching the dough. If a hole forms or you need to extend the edges on the side, it is better to cut off and press excess dough to form a patch.
Whisk an egg white with a tablespoon of waterand brush it on the top of the dough and around the edges for a shiny golden finish.
Dust the crust with sugar to give it a nice crunch.