01 - Rinse the corned beef brisket under cold water to remove excess brine. Place in a large stockpot.
02 - Add water, beef broth, spice packet, bay leaves, peppercorns, allspice berries (if using), onions, and garlic to the pot. Bring to a boil over high heat.
03 - Reduce heat to low, cover, and simmer for 2 hours, skimming any foam from the surface.
04 - Add potatoes and carrots to the pot. Simmer, covered, for 30 minutes.
05 - Add cabbage wedges. Simmer, covered, for an additional 15–20 minutes, until all vegetables are tender.
06 - Remove the brisket from the pot and let rest for 10 minutes. Slice against the grain.
07 - Arrange sliced brisket and vegetables on a platter. Ladle some cooking broth over the top for extra flavor. Serve hot.