In the bowl of a food processor process the flour with some salt. Add the chilled shortening and butter at once and pulse the machine for 15 seconds until the fat is broken up into oatmeal sized pieces.
Add 2 tablespoons of ice water and process; if the dough is dry, add more water, one tablespoon at a time. Be sure your dough holds together and absorbs enough water. If it is too dry you'll have a hard time rolling it out.
Divide the dough into two pieces, one slightly larger than the other and roll out larger half into a 12inch circle.
Line a 10inch deep glass pie plate with the 12-inch circle and chill the dough. Roll out other half into a 10 1/2inch round for top crust and transfer to a baking dish and refrigerate.