Add beef, mushrooms, onion, garlic, broth, Worcestershire sauce, pepper, and dill to a 6 quart slow cooker. Stir to mix.
Cover and cook on low for 8 - 9 hours.
Cook the egg noodles to al dente per their package directions, then add to the slow cooker along with the sour cream and mustard. Stir then let cook another 15 minutes.