Open the corned beef bag and take out the spice packet.
Place the corned beef in a large 7 or 8 quart Dutch oven and sprinkle the spice packet on top. Add the Bay leaves, garlic, and peppercorns.
4 lb corned beef flat, 2 Bay leaves, 3 cloves garlic, 6 peppercorns
Cover the corned beef with the beef broth and any additional water needed to just barely cover the corned beef.
8 cups beef broth, water
Bring to a boil, then reduce heat to a simmer. Simmer for 50 minutes per lb.
Add the chunked carrots to the Dutch oven and continue to simmer for 15 minutes.
4 large carrots
After 15 minutes, add the quartered potatoes and simmer an additional 15 minutes.
1½ lbs potatoes
Quarter the cabbage, leaving the core so that the cabbage doesn't scatter in the pot and when transferring to a platter.
Add the cabbage and onion next, and simmer for 15 minutes. Cabbage will be bright green and slightly firm still.
1 head cabbage, 1 large onions
Transfer the corned beef to a serving platter. Let the corned beef rest for 10 - 15 minutes, then before slicing, then slice. Heap up the carrots, potatoes, and cabbage around the sliced corned beef and serve at once.