Heat the oil in a skillet on medium-high heat. Reduce the heat to medium once oil is hot. Place the onion on the bottom of the pan. In a large bowl, mix the egg, beef, water, bread crumbs, onion powder and garlic salt. Press meat into the bottom of the bowl to form a rounded loaf. Invert the bowl to remove and place the loaf on top of the onion. Place the sliced potatoes around the loaf and the carrots atop the potatoes. Sprinkle the entire thing with additional seasonings if desired. Cover and cook for about 1 hour. After 30 minutes turn the meatloaf over and stir the vegetables. Additional water may be added also.