01 - Rinse the corned beef brisket under cold water and pat dry. Place it in the bottom of a large slow cooker.
02 - Sprinkle the included spice packet (or mustard seeds, if using) over the meat.
03 - Add the onion, garlic, carrots, and potatoes around the sides of the brisket.
04 - Pour in the beef broth and water until the meat and vegetables are just covered. Add bay leaves and black peppercorns.
05 - Cover and cook on LOW for 8 hours, or until the beef is fork-tender.
06 - With 1 hour remaining, carefully add the cabbage wedges to the slow cooker, tucking them around the beef and vegetables.
07 - Once done, remove the corned beef and let it rest for 10 minutes before slicing against the grain.
08 - Serve the sliced corned beef with the cooked potatoes, carrots, and cabbage, ladling some broth over everything if desired.