1. Mix the flour and salt in a food processor fitted with a steel blade.  Scatter the butter pieces over the flour mixture, tossing to coat the butter with a little of the flour.  Cut the butter into the flour with five 1-second pulses.  Add the shortening and continue cutting it in until the flour is pale yellow and resembles coarse cornmeal, with butter bits no larger than small peas, about four more 1-second pulses.  Turn the mixture out into a medium bowl.

2. Sprinkle 3 tablespoons of ice water over the mixture.  With the blade of a rubber spatula, use a folding motion to mix it in.  Press down on the dough mixture with the broad side of the spatula until the dough sticks together, adding up to 1 T more ice water if the dough will not come together.  Shape the dough into a ball, then flatten into a 4" wide disk.  Wrap in plastic wrap and refrigerate for 30 minutes, or up to 2 days, before rolling.

3. When the pie filling is ready, roll the dough on a floured surface to approximate an 11"x15" rectangle, about 1/8" thick.  If making individual pies, roll the dough 1/8" thick and cut 6 dough rounds about 1" larger than the dish circumference.  Place the dough over the pot pie filling, trimming the dough to within 1/2" of the pan lip.  Tuck the overhanging dough back under itself so the folded edge is flush with the pan lip.  Flute the edges all around.  (Alternatively, don't trim the dough, and tuck the overhanging dough down the pan side).  Cut at least four 1" holes in a large pot pie or one 1" vent hole in smaller pies.  Proceed with Pot Pie 3 recipe.