Mix the first four ingredients until gooey. I use a food processor with a plastic dough blade. My grandma did it by hand I am sure. In a separate dish beat the egg, vinegar and water together. Slowly add them to the flour mixture either using your hands or the food processor. This is smooth, sticky, and fragile dough.
Place in the fridge for 15-30 minutes before you roll out on a floured board. You can leave the dough in the fridge for up to a week or freeze.
This is enough dough for one large pie bottom and top or two regular pies with lattice tops.
To make lattice tops I use a small cutting board as a straight edge and cut long strips that I then weave one over the other. After woven I use a fork to crimp the edges. Click here to enlarge below image.