Rinse the corned beef brisket and pat it dry. Place the brisket fat-side up in a large Dutch oven along with the spice packet and bay leaves. Add enough water to just cover the meat
After simmering for about 2 1/2 to 3 hours, add the potatoes and carrots. Let them cook for 15 minutes before adding the cabbage wedges and onion.
Remove the brisket from the pot and let it rest for 10 minutes. Slice the meat against the grain. Return the sliced beef briefly to the pot to mix with the vegetables.