Preheat Nesco roaster to 250F.
Place brisket in Nesco roaster. Pour beer over the meat, and place onion sections on top. Season with garlic, salt and pepper. Combine the barbeque sauce, molasses and liquid smoke; pour over the roast.
Bake for 6 to 8 hours, or until beef is fork tender. Remove from the roaster and let stand for about 10 minutes before slicing across the grain into 1/8� slices.