Have the butcher grind the meat a couple of times. Soak the bread in water. While it is soaking, mince and saute the onion and mash the potatoes. Now mix all the ingredients in a large bowl; keep working the mixture until you have a smooth, spongy mass. It is best to work the mixture by hand. Heat butter (or fat) in a frying pan. Shape the balls by using a spoon and the palm of your hand, both wet. Brown evenly in the butter, shaking the pan meanwhile to keep the round shape. Remove to a kettle. Repeat until the meat mixture is used up. Make the gravy.