Cut apple in tiny cubes and mix it into the meat with yolks and a generous pinch of salt and pepper.
Form meatballs the size of a big walnut and roll them into the flour.
Melt the butter in a frying pan, add chopped onion and let it sautee until soft; add meatball, let them get brown gold on all sides then add the sugar and white wine keeping fire high for a minute.
Keep cooking on low fire, with a lid on, for about 20 minutes.
I think they are better warm than hot.