Place the beef stew meat, sliced mushrooms, diced onion, and minced garlic in the slow cooker.
In a small bowl, whisk together the beef broth, Worcestershire sauce, paprika, salt, and black pepper. Pour the mixture over the beef and vegetables.
Cover and cook on low for 7 to 8 hours or on high for 4 hours until the beef is tender.
In the final 30 minutes, whisk the flour into the sour cream until smooth. Stir this mixture into the slow cooker to thicken the sauce.
While the sauce thickens, cook the wide egg noodles in a large pot of salted boiling water according to package directions. Drain well.
Serve the beef and mushroom mixture over the hot noodles and sprinkle with chopped parsley.