Peel, wash and dice the potatoes. Clean, wash and halve the beans. Cook both in boiling salted water for about 10 minutes and drain. Wash and dice the cured pork loin. Fry in hot oil while turning for about 3 minutes. For the sauce, peel and chop the onion. Heat the fat and sauté the onion.
Sauté the flour in it. Add milk while stirring constantly and bring to the boil. Season with salt and pepper, mustard and dried marjoram. Put potatoes, beans and sliced pork in an ovenproof dish. Pour sauce over them and sprinkle with cheese. Cook in the preheated oven (electric cooker: 200 °C / gas: level 3) for about 20 minutes. Serve garnished with fresh marjoram