1 pound medium potatoes - peeled and seeded
1/2 cup vegetable oil
1 onion, diced
1 (10 ounce) can condensed cream of potato soup
1/2 cup milk
2 tablespoons lemon juice
4 eggs
2 cups liquid nonfat milk
1/2 teaspoon salt
1/2 teaspoon ground black pepper
1 cup chopped celery
Preheat oven to 350 degrees F (175 degrees C).
Line a large baking sheet with aluminum foil, cutting the foil to fit the baked potatoes. Rub the oil into the potatoes and onion, and sprinkle with the onion. Season with salt, pepper, celery, and milk.
Bake in preheated oven for 40 minutes.
Remove the foil and place on a cooling rack. Place the potatoes in the oven, and it will come to a rolling boil, adding water if necessary. Cover, and let cool slightly.
Meanwhile, stir the potato soup into the soup, and pour the milk mixture over the potatoes. Cover, and cook for 25 minutes.
Remove the foil from the potatoes, drizzle with remaining lemon juice, and sprinkle with salt, pepper, celery, and Parmesan cheese.
Bake in preheated oven for 30 to 35 minutes, or until tender. Serve hot or cold.