3 medium onions, cut into wedges
3 pounds bone-in beef short ribs, trimmed of fat
1 bay leaf
12 ounces light beer or nonalcoholic beer
2 Tbsp brown sugar
2 Tbsp Dijon mustard
2 Tbsp tomato paste
2 tsp dried thyme
2 tsp beef bouillon granules
1 tsp salt
1/4 tsp pepper
3 Tbsp all-purpose flour
1/2 cup cold water
Place onions in a 5-quart (or larger) slow cooker; add ribs and bay leaf. Combine the beer, brown sugar, mustard, tomato paste, thyme, bouillon, salt and pepper. Pour over meat. Cover and cook on low for 8-10 hours or until meat is tender.
Remove meat and vegetables to a serving platter; keep warm. Discard bay leaf. Skim fat from cooking juices; transfer juices to a small saucepan. Bring liquid to a boil. Combine flour and water until smooth. Gradually stir into the pan. Bring to a boil; cook and stir for 2 minutes or until thickened.