Sift first 4 ingredients together.  Add 1/4 cup cheese and potatoes to flour mixture and mix together.  Add water and oil; mix to make a soft dough.  Turn onto floured surface and shape into 8 inch circle.  (I just used my hands to do this.)  Place on a greased pan.  Sprinkle with remaining cheese.  Bake at 425 for 25-30 minutes.  Cool on wire rack.