Mix flour, sugar, and salt in a bowl. Stir to combine.
Cut in COLD butter or lard
Fat is fully cut in when the flour is in crumbly pea size pieces.
Mix egg and vinegar together in a small bowl, then add to flour mixture along with 3 tablespoons of ice cold water.
Continue adding water, one tablespoon at a time, until the dough just holds together, without crumbling, when pressed into a ball.
Wrap dough in plastic wrap and chill in the fridge for 15 minutes.
Divide dough into four equal balls, press out into a disc and either freeze or roll out to bake pies.