Wash the leek and potatoes, chop the onion and leek into small pieces. Season the minced meat to taste and fry it in a medium-sized saucepan with the onion. Add the leek and cook for about 5 minutes. In the meantime, peel the potatoes and cut them into cubes. Add the potatoes and stock and simmer until the potatoes are cooked through (15-25 minutes). Finally stir in processed cheese and season again to taste.