Heat a large skillet over medium heat and pour in oil.
Saute onion in oil until browned, 5 to 10 minutes. Set aside. In the same skillet over medium heat, saute the ground beef for 5 to 10 minutes, or until browned.
Place a layer of potatoes into a lightly greased 9x13 inch baking dish.
Sprinkle with salt and pepper to taste and then spread a layer of ground beef over the potatoes, followed by a layer of onions.
Repeat layers, ending with potatoes. In a medium bowl, combine the soup with the water.