In large mixing bowl, combine KELLOGG'S ALL-BRAN cereal and milk. Let stand about 5 minutes or until cereal softens.
Add beef, pork, onions, eggs, salt, pepper and nutmeg to cereal mixture. Mix well. With floured hands, portion and shape into small balls about 1-inch in diameter.
Heat margarine in large fry pan. Add meat balls and cook slowly over low heat, turning until browned on all sides. Cover pan. Cook on low about 30 minutes or until meat is tender and done (160 degrees F). If pan becomes dry, add 1/4 cup water or beef bouillon.
Just before serving, drain off any excess fat. Stir in sour cream. Heat thoroughly. Add additional salt and sprinkle with nutmeg, if desired.