Mix dry ingredients together. Cut shortening into dry ingredients until mixture is the consistency of coarse meal. Combine vinegar and egg and add enough water to make one cup liquid. Add liquid to dry ingredients and mix until dough forms a ball. Avoid overmixing; once it sticks together, that's enough.
Divide dough and pat out with hands into desired shape on floured sheet of wax paper (lots of flour!). Put another floured sheet on top (more flour!) and smooth with rolling pin. Transfer to pie dish using the wax paper. Yields five or six 9-inch crusts. Store unused dough (in rolled-out crusts or in balls) in freezer, tightly wrapped.