1) In a medium bowl, whisk together the flour and salt.
2) Cut in the shortening until it's in lumps the size of small peas.
3) Dice the butter into 1/2" pieces, and cut into the mixture until you have flakes of butter the size of your fingernail.
4) Add the water, 2 tablespoons at a time, mixing with a fork as you sprinkle the water into the dough.
5) When the dough is moist enough to hold together when you squeeze it, transfer it to a piece of wax or parchment paper. It's OK if there are some dry spots in the pile. Use a spray bottle of water to lightly spritz these places; that way you'll add just enough water to bring the dough together without creating a wet spot.
6) Fold the dough over on itself three or four times to bring it together, then divide it in half and pat it into two disks 3/4" thick.
7) Roll the disk on its edge, like a wheel, to smooth out the edges. This step will ensure your dough will roll out evenly, without a lot of cracks and splits at the edges later. Wrap in plastic and refrigerate for 30 minutes before rolling.
8) Lightly grease a 9-inch pie pan that's at least 2 inches deep. This will make serving the pie easier after it's baked.
9) Combine the sliced apples and lemon juice in a large mixing bowl.
10) In a small bowl, whisk together the sugar, flour, cornstarch, salt, and spices. Sprinkle the mixture over the apples, and stir to coat them. Stir in the boiled cider or apple juice concentrate.
11) Roll out half of the pastry to a 13" circle. Transfer it to the prepared pan, and trim the edges so they overlap the rim of the pan by an inch all the way around.
12) Spoon the apple filling into the pan. Dot the top with the diced butter.
13) Roll out the remaining pastry to an 11" circle. Cut decorative vent holes, if desired; or weave a lattice. Carefully place the pastry over the apples.
14) Time to preheat the oven to 425°F.
15) Roll the overhanging bottom crust up and over the top crust, pinching to seal the two.
16) Flute the edges of the pie, then place it in the refrigerator for 10 minutes to firm up the crust while the oven finishes heating.
17) Place the pie on a parchment-lined baking sheet. Bake the pie for 20 minutes at 425°F, then reduce the oven temperature to 375°F and bake for 40 minutes more, until you see the filling bubbling inside the pie. Check the pie after half an hour of baking time, and cover the edges with foil or a pie shield to keep them from browning too quickly.
18) When the pie is done, remove it from the oven and cool it completely before slicing.