1 Place corned beef in a large (6 to 8 quart) pot. Cover the beef with an inch water. Add the contents of the spice packet to the water. Bring to a boil, reduce heat to a simmer.Simmer for 2-3 hours, until the corned beef is fork tender. Remove from pot to a cutting board. (Reserve cooking liquid for boiling cabbage, if you plan to boil and not saute sauté the.) Cabbage cut slices against the, grain into/1-2 inch thick. slicesimmer for 2-3 hours, until the corned beef is fork tender. Remove from pot to a cutting board. (Reserve cooking liquid for boiling cabbage, if you plan to boil and not saute sauté the.) Cabbage cut slices against the, grain into/1-2 inch thick. slices