Peel and wash the potatoes and cook in salted water for about 20 minutes.
In the meantime, clean, wash and drain the chard. Chop the chard stems and 4 leaves separately. Cut the remaining leaves roughly. Wash the tomatoes. Peel and finely chop onion and garlic.
Wash the rosemary, dab dry, remove the needles and also chop finely. Wash parsley, shake dry and chop finely.
Drain the potatoes and mash them finely with a potato masher. Place the hot mashed potatoes in a bowl and immediately knead in the potato flour and egg. Season vigorously with salt, pepper and nutmeg.
Knead in chopped chard leaves. Form 8 meatballs from the potato mixture. Heat 2 tablespoons of oil in a large frying pan. Fry the potato cakes for 3-4 minutes on each side until golden brown.
In the meantime heat 2 tablespoons of oil in a wide saucepan. Brown the tomatoes in it for about 3 minutes until they burst open easily, take them out. Fry the onion, garlic, chard stems and rosemary in hot frying fat.
Add the rest of the chard and 100 ml of water. Bring to the boil and let the chard briefly collapse.
Add tomatoes and heat up again briefly. Season everything with salt and pepper. Stir the crème fraiche until smooth and drizzle over it. Serve with meatballs. Sprinkle with parsley.