In a 5-quart slow cooker, make a bed on the bottom with the diced onions. Place the beef short ribs on top. Add the brown sugar, garlic, thyme, and flour, and using tongs, toss to coat with the meat (try to leave the onion bed on the bottom).

Pour the soup and beer over all.

Cover and cook on low for 8 to 9 hours, or until the beef is fork-tender.

Serving tip: Serve the beef with the onion gravy on top, with mashed potatoes or noodles on the side (with additional gravy).