Finely mince the onion and saute in butter. Set aside. In a small bowl mix together sour cream and bread crumbs. I like to use Italian bread crumbs. In a large bowl combine the rest of the ingredients. Add in onions and sour cream mixture and mix very well. Roll the meat into small balls around the size of a walnut. Fry in butter until outside it brown. If you don't feel like standing over the stove, put meatballs in a baking dish with a little oil and water and cook at 350F for 1 hour. Frying is worth the extra work. Serve with lingonberries (cranberries are a good substitute) or with sour cream and beef gravy sauce heated.