Preparation

• Combine the flour and salt in a large mixing bowl or a food processor. Add the shortening and cut it in with a pastry blender or two knives (or pulse the processor) until the largest pieces of shortening are about the size of fat peas. Transfer to a large mixing bowl if using the food processor. In a small bowl, beat together the egg, 2 Tbs. of the ice water, and the vinegar; add this to the flour mixture. Work the liquid evenly through the dough with the tips of your fingers until it can be collected in a rough ball. If the dough is too dry to come together, gradually sprinkle a few drops of the remaining water over it and continue to work gently until it comes together.
• Cut the dough in half and shape each into a ball. Flatten each ball into a disk and wrap tightly in plastic. Chill for at least 4 hours or up to three days. (Freeze one if you like, to save for another purpose.)
• About 2 hours before baking, remove one of the dough disks from the refrigerator so it can warm up just enough to roll without cracking. Unwrap the dough and roll it between two sheets of waxed paper into a round about 12-inches in diameter. Peel off the top sheet of waxed paper. Invert a 9-inch glass pie plate and center it on the dough. Slide one hand under the bottom sheet of waxed paper, position your other hand flat on the pie plate, and quickly flip the plate and dough over. Peel off the waxed paper and gently press the dough down into the plate. With a paring knife, trim the dough to within 3/4-inch of the rim of the plate. Fold the dough under and crimp the edges. Use the trimmings to patch any cracks or bare spots. Wrap the shell loosely with plastic wrap and chill for 2 hours or up to 24 hours.