Peel and finely chop the onion. Knead minced meat, onion, egg and breadcrumbs. Season with salt, pepper and paprika. Form 12 small, flat meatballs from the minced meat mixture and fry in hot oil for about 10 minutes. Turn several times in between.
Cut open the bread roll. Spread the lower halves with ketchup. Place one meatball on top of each. Spread the salad on top. Sprinkle with chopped parsley and cover with the other roll half