Peel and chop the potatoes. Peel and chop the onion and fry in the oil. Add the potatoes and fry briefly. Cut the savoy cabbage into fine strips, add to the potatoes and fry.
Add three quarters of the hot broth, season everything with salt and pepper and stew covered for about 15 minutes.
Mix the processed cheese and remaining stock, stir into the pan and let everything melt while turning. Dice the tomato and sprinkle over it. Season again with salt and pepper.