Pat dry. Place it in a large Dutch oven, fat side up, along with the spice packet.
Pour in the lager and beef broth, just enough to cover the meat. Add the onion, bay leaves, cinnamon stick, and peppercorns.
Bring the pot to a gentle simmer over medium heat. Once bubbling, reduce heat to low, cover with a tight-fitting lid, and cook for 4-5 hours or until the meat is fork-tender and reaches the internal temp of 145º.
Add the potatoes and carrots to the pot, cover again, and simmer for 25 minutes. Then, add the cabbage wedges and cook for another 20 minutes, until everything is tender.
Transfer the corned beef to a cutting board and let it rest for 10 minutes before slicing against the grain.
Slice the corned beef and serve it alongside the vegetables with a ladle of the flavorful broth over top.
Notes
When adding the corned beef to the dutch oven, keep the fat side up so that the juices from the fat render down into the meat. This helps keep it very juicy and tender.When adding the liquids, use just enough to cover the top of the brisket/corned beef.Keep the flame on a low simmer throughout the cooking time, and hold off on adding the cabbage, carrots, and potatoes until 45 minutes before the cooking timer goes off. This alleviates any overcooking of the vegetables.