Sift together flour, salt and sugar on a cutting board

Work butter into dry ingredients, kneading with your palm, until it is an even mixture

Make the dough into a ball and roll out about 3/4 of an inch thick

Place in a pan with high sides to prevent the short bread from browning too quickly around the edges, and prick the surface with a fork

Bake in a very moderate oven, 300F., for 35 minutes

Allow the short bread to stand an hour or two before serving so that it becomes crisp and thoroughly set, then slice into serving pieces.