Soak the roll in milk for about 1 hour. Then squeeze out gently and dispose of the milk.
Peel and finely chop the onion. Cut the capers into small pieces.
Mix the minced meat well in a bowl with the bread roll, egg, spices, mustard and ketchup, season to taste and season if necessary. Then add the onions and capers and mix well again. If the mass is too thin, you can add some breadcrumbs.
Shape the meatballs out of the mixture and turn them in breadcrumbs.
Heat oil or butter in a pan and fry the meatballs in it.
This results in about 8 meatballs, depending on the size you want.