Wash the potatoes and cook in plenty of boiling water for about 20 minutes. In the meantime, wash and clean the beans and cook them in boiling salted water for about 15 minutes. Take them out and rinse with cold water.
Onions peel and cut into slices. Cut the meatloaf into pieces. Rinse potatoes under cold water, drain and peel the skin. Cut potatoes into slices. Heat 1 tbsp. clarified butter in a large pan.
Fry the beans, onions and Leberkäse for about 5 minutes, turning. Season with salt, pepper and marjoram, take out. Heat 2 tablespoons of clarified butter in the pan. Fry the potatoes for about 10 minutes while turning.
Season with salt and pepper. Add Leberkäse, beans and onion, warm up briefly. Fold in mustard. Season to taste with salt and pepper.