Soak the roll in water, then squeeze it out as well as possible. Mix the minced meat with parsley, peppermint, chopped onions, cumin, egg, parmesan and the squeezed roll in a bowl and season well with salt and pepper. Cover and place in the fridge for about 30 minutes.
Shape the meat dough into small meatballs with slightly moistened hands, turn the balls in flour and fry them in a pan in olive oil until they are crispy brown. Take the balls out of the pan and let them drain a little on kitchen paper.
In the meantime, cut the second onion into very thin rings. In a new pan, fry the onion rings in a little olive oil, add the meatballs and deglaze with the balsamic vinegar. Swirl briefly and serve sprinkled with the coarsely chopped mint.
The balls taste warm and cold and also enrich a cold buffet.