Spread out deep-frozen French fries on a baking tray lined with baking paper. Bake in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for approx. 20 minutes. In the meantime, rinse vegetables in a sieve and drain. Peel and finely dice the onions. Cut mozzarella into small cubes.
Knead the ground pork, egg, mozzarella, 1 onion, breadcrumbs and 3 tablespoons of vegetables. Season with salt and pepper. Form 4 flat steaks. Heat the oil in a grill pan. Fry the steaks for about 5 minutes on each side. Melt butter in another pan. Fry the remaining onion and vegetables for about 5 minutes, stirring continuously. Wash the parsley and put 4 leaves aside for garnishing. Cut remaining leaves into strips and stir into the vegetables.
Melt butter in another pan. Fry the remaining onion and vegetables for about 5 minutes, stirring continuously. Wash the parsley and put 4 leaves aside for garnishing. Cut remaining leaves into strips and stir into the vegetables. Season with salt, pepper and sugar. Serve French fries, vegetables and steaks in portions garnished with parsley