Whisk salt and flour together in a bowl.

With a pastry cutter, cut shortening and butter into flour mixture until chunks are the size of small peas.

Stir in buttermilk and vegetable oil with a fork until dough is moistened and beginning to gather together.

Form the dough by hand into a compact shape

Divide dough in half and roll each half into a ball.

Roll out each ball into required size and shape between two sheets of parchment paper.