Wash the potatoes and cook in boiling salted water for about 15 minutes. Drain and cut into large pieces. Wash, clean and slice the zucchini. Wash and halve the tomatoes. Peel and finely chop the onions.
Wash the marjoram, shake dry and pluck leaves from the stalks. Wash the cured pork, dab dry and dice.
Heat 1 tablespoon of oil in a saucepan and sauté about half the onions in it. Deglaze with wine and let it simmer for a short time. Stir in vinegar, cream and mustard, season with salt and pepper.
Heat 2 tablespoons of oil in a frying pan, fry the smoked pork in it for approx. 5 minutes, turning it over, and take it out. Fry the potatoes in the pan for about 10 minutes, turning them over. Add the zucchini and the remaining onions about 3 minutes before the end of the frying time.
Fold in the cured pork, tomatoes and marjoram. Season with salt and pepper. Arrange potato pan, add sauce.