1In 3 1/2- to 4-quart slow cooker, place beef, mushrooms, onion, pepper and bouillon granules.
2Cover and cook on Low heat setting 8 to 9 hours.
3About 20 minutes before serving, cook and drain noodles as directed on package. Gently stir sour cream and thyme into drained noodles.
4Sprinkle flour over beef mixture in cooker; gently stir into mixture. Increase heat setting to High. Cover and cook 3 minutes. Serve beef mixture over noodles; top with tomato.