In a large bowl, mix flour and salt.
Cut in the shortening until pea sized. It should look crumbly.
In a 1 cup measuring cup beat the egg. Add in the vinegar and then top off with milk.
Add the wet ingredients to the dry and mix well with your hands. If dough is sticky, add 1-2 tbsp. flour.
Roll into a ball and cover with plastic wrap. Chill for a minimum of 20 minutes prior to rolling out. Freezes well.