Tear or cut the rolls into small pieces or cubes (or grate into crumbs). Beat the eggs in a bowl, then pour over the roll pieces. Let soak for 5 minutes until well absorbed.
Wash, dry, and chop the parsley finely. Dice the onions very finely. Sauté the onions in butter or clarified butter over medium heat for 2-3 minutes until translucent. Let cool for 1 minute.
Combine the minced meat, soaked bread-egg mixture, parsley, cooled onions, and mustard in a bowl. Knead together until well mixed. Season to taste with salt, pepper, and hot paprika powder. Shape into 8-10 meatballs.
Heat oil in a pan over medium heat. Fry the meatballs for about 5 minutes on each side until golden brown and cooked through (internal temperature of 63°C / 145°F).