Onions peel, halve and finely dice. Mix the mince and half of the onions, season with salt, pepper and paprika. Form 10-12 large meatballs with the help of an ice cream portioner. Heat the oil in a large frying pan. Fry the meatballs for about 5 minutes while turning them over, take them out and put them aside.
Sauté the remaining onions in the hot frying fat for about 1 minute, dust with sugar and deglaze with vinegar, tomatoes and cream, season well with salt and pepper and simmer gently for about 5 minutes.
Wash the spinach, dab dry and add to the sauce about 1 minute before the end of the cooking time and let it collapse. Place the meatballs in the pan. Grate the cheese and spread over it. Bake in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: see manufacturer) for approx. 20 minutes until the cheese is golden yellow. Baguette tastes good with it.