01 - Rinse the corned beef brisket under cold water to remove excess brine. Pat dry thoroughly.
02 - Place the brisket fat side up in a large slow cooker. Sprinkle the provided spice packet, additional peppercorns, and bay leaves evenly over the meat.
03 - Arrange onion, garlic, potatoes, and carrots around the brisket in the slow cooker.
04 - Pour in beef broth and water until the meat and vegetables are just covered.
05 - Cover and cook on LOW setting for 8 hours, or until the brisket is very tender.
06 - About 2 hours before the end of cooking, place cabbage wedges on top of the brisket and vegetables. Re-cover and continue cooking until cabbage is tender.
07 - Transfer the brisket to a cutting board and let rest for 10 minutes. Slice against the grain for maximum tenderness.
08 - Arrange the sliced brisket and vegetables on a serving platter. Spoon a little of the cooking liquid over the top if desired. Serve hot with grainy mustard or horseradish sauce.