Sift flour, sugar and salt into bowl. Whip oil and milk together. Pour over flour mixture, and mix with a fork. Pat 2/3 of dough into a pie plate. Use filing of your choice. Crumble rest of dough on top (except on cream pies). (I like to add brown sugar, crushed walnuts and cinnamon to the mixture for my apple pie). Bake as for any pie.