In a large bowl mix together flour, salt, baking poder and baking soda. Cut in the shortening until the mixture forms coarse crumbs.
Make a well and add 1 cup buttermilk. Quickly cut dry ingredients into the buttermilk to form a sticky dough. Add more buttermilk as necesary.
Turn out the dough on a floured surfaceand foldover itself 3-4 times. Press out to 1 1/2 inches thick and section with a 3-inch cutter. Arrange biscuis on an ungreased cooke sheet and brush with buttermilk before baking 20-25 minutes or until risen and golden at 375F.