Add the beef stew meat, diced onion, sliced mushrooms, and minced garlic to the slow cooker.
Pour in the cream of mushroom soup, beef broth, and Worcestershire sauce. Sprinkle the paprika, salt, and black pepper over the top.
Stir everything together until well combined, then cover and cook on low for 7 to 8 hours or on high for 4 hours.
About 20 minutes before serving, cook the egg noodles according to package directions and drain them.
Turn off the slow cooker and stir in the sour cream until the sauce is smooth.
Serve the beef mixture over the cooked egg noodles and sprinkle with chopped fresh parsley.