Combine flour and salt in a medium bowl; cut in butter and shortening with a pastry blender until mixture is crumbly. Sprinkle milk, 1 tablespoon at a time, evenly over surface; stir with a fork until dry ingredients are moistened.
Shape into a ball; roll pastry to 1/8-inch thickness on a lightly floured surface. Cut dough into 6 (5-inch) circles; fit into 6 (4-inch) tart pans with removable bottoms. Prick bottoms of tart shells with a fork; place on a baking sheet. Bake at 450