Scald 2 veal kidneys, remove the membranes, chop fine, and add salt. Fry 1 finely chopped medium onion in 1 spoon butter, mix with the kidneys, and add 2–3 ground rusks. Beat in 2 eggs, 2 spoons sour cream, and a little pepper. Using a mortar and pestle, pound the mixture thoroughly. Sprinkle with salt and nutmeg, form into balls, and roll in rusk crumbs. Just before serving, drop the balls into bouillon. Meatballs may also be made from the kidneys of suckling pigs and served with suckling pig soup.