Trim fat from roast. Cut to fit crockpot. Put meat in, cover with onions, bay leaf. Combine beer, chili sauce, sugar, thyme, salt, pepper, and garlic; pour over meat.

Cover and cook on low for 10-12 hours or high for 5-6 hours.

Transfer meat to platter and keep warm. Discard bay leaf. Skim fat from cooking juices. Measure 2 1/2 cup juices and place in a saucepan. Combine cornstarch and water; add to saucepan. Cook and stir till thick and bubbly. Cook for 2 min. More. Pass with meat.