Coarsely grate potatoes and rinse thoroughly. Grate onions, mix with eggs and add salt, pepper and parsley; blend thoroughly. (Potatoes and onions may be grated separately in blender.) Pour into greased six-cup ring mold or shallow casserole. Sprinkle oil on top. Bake at 400° one hour or until top is golden. If you use ring mold, cool 5 minutes and unmold on heated platter. Center can be filled with a vegetable; i.e., peas, saut?ed mushrooms or glazed carrots. Can also be made au gratin by adding 1/2 to 1 cup grated Cheddar or Swiss cheese; however, a casserole dish should be used if cheese is added.