Remove corned beef from the package. Rinse it under cold water to remove excess salt. Pat dry with paper towels. This helps prevent the meat from being too salty.

Place the corned beef in a large pot or Dutch oven. Add water until the meat is mostly covered. Add the spice packet, peppercorns and bay leaves.

Add quartered onion and smashed garlic cloves to the pot. These aromatics add depth and flavor to the cooking liquid. They will also infuse the meat with a rich aroma.

Bring water to a boil over medium-high heat. Reduce heat to low, cover, and simmer for 2 ½–3 hours. Check occasionally to ensure it stays submerged in liquid.

Add carrots and potatoes during the last 45 minutes of cooking. Add cabbage wedges during the last 15 minutes. This prevents overcooking and keeps vegetables tender.

The corned beef is done when it is fork-tender and easily slices against the grain. Remove meat first and let it rest for a few minutes before slicing.

Slice corned beef thinly against the grain. Arrange on a serving platter with cooked vegetables. Spoon a little cooking liquid over the meat to keep it moist.