Place the beef into a 5-quart slow cooker. Add the brown sugar, garlic, thyme and flour and toss to coat. Pour the soup and ale over the beef mixture.
Cover and cook on LOW for 8 to 9 hours or until the beef is fork-tender. Spoon off any fat from the surface of the sauce. Serve with the mashed potatoes.
Time-Saving: Or you may cook this recipe on HIGH for 4 to 5 hours.