In a bowl, combine bread and milk. Add the egg, onion, salt and pepper; mix well. Crumble beef over mixture and mix well. Shape into 1-in. balls. In a large skillet, brown meatballs in small batches over medium heat until no longer pink. Drain on paper towels.
In a large saucepan, melt butter. Stir in flour until smooth. Gradually add consomme; bring to a boil. Reduce heat; add the mushrooms, parsley, Worcestershire sauce and bouillon. Add meatballs; simmer, uncovered, for 30 minutes, stirring occasionally. Remove from the heat; stir in sour cream. Serve over noodles if desired. Garnish with parsley. Yield: 6-8 servings.