Spray the inside of a large slow cooker with cooking spray. ( I use a 7 quart size slow cooker).
Place the stew meat, mushrooms (if using), onion soup mix, beef broth and Worcestershire sauce in slow cooker. Cover with lid and cook on low heat for 5 to 6 hours.
In a medium bowl combine sour cream, cream cheese and heavy whipping cream. Whisk to combine then stir in to meat mixture. Season with a little pepper.
Cover with lid and let it warm up for another 20 minutes.
Serve over cooked egg noodles and enjoy!