Meerrettich kartoffeln is a traditional dish consisting of potatoes in horseradish cream sauce. The dish is usually made with a combination of potatoes, root horseradish, milk, butter, onions, flour, sugar, salt, and parsley. The horseradish is grated and soaked in milk.
The potatoes are boiled, peeled, and sliced. The onions are minced, sautéed in butter, sprinkled with flour, and stirred until the flour is absorbed. Water, milk, and grated horseradish are added to the pan in order to create a creamy sauce that's stirred until smooth and thick.