In a medium bowl, whisk together the flour and salt., Add the shortening, working it in until the mixture is evenly crumbly., Add the butter to the flour mixture, and work it in roughly with your fingers, a pastry cutter, or a mixer. Don't be too thorough; the mixture should be very uneven, with big chunks of butter in among the smaller ones., Add 2 tablespoons of water, and toss to combine., Toss with enough additional water to make a chunky mixture. It should barely hold together when you squeeze a handful, though the remainder may look quite dry., Shape the dough into a disk about 1" thick, and refrigerate it for 30 minutes or longer; this resting period allows the flour to absorb the water, making the dough easier to roll out. If you decide to let the dough chill longer than 30 minutes allow it rest at room temperature for 10 to 15 minutes before rolling, to allow the butter to soften up a bit., When you're "ready to roll," remove the dough from the fridge. Roll the dough to the size needed (about 12" for a 9" pie). Place it in a pie pan, and refrigerate it while you prepare your filling. , Fill and bake your pie as directed in the recipe.