Fill a large stock pot with enough water to cover corned beef. Place beef, and contents of seasoning packet if included with purchase, in stock pot and bring to a simmer. Cook for 2 to 3 hours, until a toothpick or wooden skewer can be inserted easily into the meet.
Preheat oven to 200 degrees. Remove beef from water and place in roasting pan with a ladle of cooking liquid. Place in oven to keep warm.
Meanwhile, place potatoes, carrots, and onion in the stock pot and bring to a boil, cooking for 10 minutes. Add cabbage and boil an additional 10 minutes.
Remove beef from oven and slice against the grain. Serve with drained vegetables.
Notes
Adapted from a call to a friend and Cook’s Illustrated