With a pastry blender, or two knives, cut in the shortening until mixture resembles coarse crumbs. Add buttermilk and mix lightly with a fork until mixture clings together and forms a soft dough. Turn dough out onto a lightly floured surface and knead gently 5 or 6 times. Divide dough in half. Repeat with remaining dough.
Place scones one inch apart on prepared pan.
Pierce tops with the tines of a fork and sprinkle with reserved walnuts. Bake for 15 to 18 minutes, or until golden brown. Cream together the butter and sugar until light and fluffy. Add egg and beat well. Add pumpkin, flour and salt and fold in by hand.