Combine flour and salt in the bowl of a food processor and process for a few seconds. Add butter slices and process until the mixture looks like coarse meal – visible little bits of butter are OK. Add water a few drops at a time just until mixture comes together. If you pick up a bit with your fingertips, it will stay together. Dump mixture onto a large piece of plastic wrap, flatten into a disk and refrigerate for one hour. (If you are making a double-crust pie, divide into two disks.) To roll out dough, sprinkle work surface lightly with flour or roll out between two pieces of plastic wrap. Roll out from the center until dough is ⅛-inch thick. Work quickly! If your kitchen is hot and the dough becomes too soft, place it in the refrigerator for a few minutes. Make the dough 2-3 inches larger than the pan size. Carefully pick up dough by draping it on rolling pin or peeling off one side of the plastic wrap and positioning it over the pie plate or tart pan. For tarts, fold dough over sides to make a double thickness remove excess at top. For single-crust pies, fold dough over rim evenly and crimp by pinching dough between your thumb. For double crust pies, add filling, then roll out top crust and place over filling. Trim edges, then crimp. Cut holes or slits in top crust to release steam.
To bake unfilled tart crusts, carefully place foil on crust and fill with rice, dried beans or pie weights to keep crust from puffing up. Bake at 375 degrees for 10 minutes or until edges just start to get color. Carefully remove foil and continue baking for about 6-8 minutes, or until the crust turns golden brown. Remove to rack to cool.