In a medium bowl, whisk together the flour and salt. Work in the shortening until it's in lumps the size of small peas.
Dice the butter into 1/2" pieces, and work it into the mixture until you have flakes of butter the size of your fingernail. Add the water 2 tablespoons at a time, mixing with a fork as you sprinkle the water into the dough.
When the dough is moist enough to hold together when you squeeze it, with no floury patches or bits of dry pastry in the bottom of the bowl, transfer it to a lightly floured work surface. Fold it over on itself three or four times to bring it together completely, then pat it into a disk 3/4" thick, rolling the disk to smooth its edges.
Wrap the pastry in plastic and refrigerate it for 30 minutes before rolling.
To prebake the crust: Preheat the oven to 400°F. Lightly grease a 9" pie pan that's at least 1 1/2" to 2" deep.
Roll the pastry into a 13" circle. Transfer it to the prepared pan, and trim the edges so they overlap the edge by an inch all the way around. Tuck the edges up and under, and flute or crimp them. Put the lined pie pan in the refrigerator to chill for 10 minutes.
Line the crust with foil or parchment paper, and fill it with pie weights or dried beans. Bake the crust for 20 minutes. Remove it from the oven, and gently remove foil or parchment with the weights or beans. Return the crust to the oven for 10 to 20 more minutes, until it's golden brown all over. If the edges of the crust start becoming too brown, cover them with a pie shield, or strips of aluminum foil. Remove the crust from the oven and cool completely.