In a large bowl, put the flour, sugar, butter, and salt. Using a pastry blender, two knives or a fork, work the butter and flour until it has the texture of oatmeal. Make a well in the center of this mixture, and pour in the egg yolk, beaten with the water. Mix with a fork, then use your hands to press the dough into a ball. Knead the dough for a few seconds to distribute the fat evenly, then re-form into a ball. Wrap in wax paper and refrigerate for a least 20 minutes. It will keep for 3 or 4 days in the refrigerator, or several weeks in the freezer.
When ready to use, put on a board that is lightly floured and roll out to slightly larger than the size desired. Roll back onto a rolling pin, slide over pan, push down in corners, cut off excess dough, crimp edges, and refrigerate until ready to use. Makes 3/4 lb.