Step 1

Preheat the oven to 300°F. Place the carrots, celery and onions in a large roasting pan. Pour 2 cups water into the pan until the water level is 1/2 inch high. Place the rinsed corned beef brisket over the vegetables. Cover the pan with aluminum foil.

Step 2

Transfer the roasting pan to the oven. Cook, covered, until the meat is very tender, five to six hours.

Step 3

Remove the corned beef brisket from the roasting pan. Discard the vegetables and cooking juices. Tent the beef with foil, and let rest for 10 minutes. Serve. To slice the beef for Reuben sandwiches, cool the corned beef for 10 minutes. Wrap it well, and place it in the refrigerator. Allow the meat to cool completely overnight. Then, slice thinly against the grain. Editor’s Tip: If you think you’ll have leftovers or plan on serving the corned beef later, save the strained cooking juices. They will keep the meat from drying out in the refrigerator.