Wash the potatoes and cook in boiling water for about 20 minutes. Then drain, quench and peel. Cut potatoes into medium sized pieces. Clean the mushrooms and clean them if necessary. Cut cucumbers into medium sized pieces. Cut slices into medium-sized cubes.
Peel and chop onion. Heat the oil in a pan and fry the diced Kasseler in it for about 3 minutes. Add potatoes, mushrooms, onion and cucumber and fry for about 5 minutes. Season with salt and pepper. Deglaze with the broth and steam for about 5 minutes. Stir crème fraîche until smooth, put it as a blob on the pan and garnish with marjoram