Bake potatoes in the oven until cooked for about 1 hour at 180 degrees. Heat oil in a saucepan with a thick bottom. Finely chop the onion and fry in oil until soft over low heat. Add flour to the onion, mix. Gradually add broth and milk to the onion, mixing well to break all the lumps. Remove the pulp from the hot potato with a spoon, just chop the cold one finely, peeling it off. Add the potatoes to the soup, cook over medium heat, stirring occasionally until the soup acquires a creamy consistency. Add salt and pepper to taste. Fry the bacon to a crunch, transfer to a napkin, so that the fat is stacked, break it into pieces. Serve the soup sprinkled to taste with bacon, cheese and green onions.