Tüften un plum is a traditional potato soup originating from northern Germany. The soup is usually made with a combination of potatoes, onions, carrots, celery, vegetable stock, prunes, bacon, oil, white wine vinegar, salt, and pepper. The onions are cooked until translucent, and then mixed with the potatoes, celery, and carrots.
The ingredients are covered with the stock and simmered until the vegetables become soft. The bacon is sautéed until crisp, and the chopped prunes are sautéed in the remaining fat. The soup is puréed and the bacon bits and prunes are added to the pot.