Your crust will need some time to chill in the fridge before rolling out, so prepare to make it about 30 minutes before you want to start making your pie.
The pie texture will be best if you make this crust in a food processor, but if you don't have one, just be sure to cut in your butter and shortening with a pastry cutter or forks. The biggest concern is that your hands don't work with the dough a lot, so the butter and shortening don't begin to melt. The flecks throughout is what will make it flaky when baked.
Preheat oven to 425°F.To start, add the flour and salt to the food processor and pulse for 2 seconds, until mixed (or mix the flour and salt in a medium-sized mixing bowl). Add the cubes of butter and chunks of shortening to the food processor (or to the bowl). Cut the butter and shortening in by pulsing the food processor until the butter and shortening are all incorporated, and finely minced into the dough (or if using a bowl, cut the butter and shortening in until it's all well distrubuted, finely, throughout the dough) - you don't want any large chunks.
Add the vinegar to the cold water, and pour the very cold water into the dough. If using a food processor, turn the processor on and pour the water in as it's mixing. If using a bowl, work quickly to incorporate the water so you don't have to handle the dough for too long.Work the dough until it comes together into a ball. If it's still a little wet, give it 1-2 kneads on a floured countertop, to incorporate a little more flour into it. Form the dough into a smooth ball and wrap with plastic wrap or stick into a ziploc bag.
Chill for 20-30 minutes.
Remove dough from fridge. Generously flour your countertop and rolling pin, and begin to roll the dough out. (If it isn't well floured the dough can stick to the counter, causing it to tear.)
Roll the dough until it's about 2-3 inches wider than your pie pan (all the way around). It should be about 1/4" thick.
Using the rolling pin, roll the flattened dough back onto the pin, and use the rolling pin to transfer it into your pie pan.
Gently press the bottom of the pie crust into the pan, to form to the shape.
Fold the excess dough over onto the top of the pie pan and pinch to form a crust, as you like it. I like to pinch it into wide waves. Don't worry about it being a little thick on the top edges, this will keep it from burning in the oven. Once pie crust is shaped to your liking, put back in the fridge to chill while you make the pie filling.