Is it raw or cooked? I start with a raw corned beef, cover it with cold water, bring it to a boil and simmer 5 minutes or so, then dump the water and cover it with fresh cold water. Bring it to a boil again and add several tablespoons of pickling spice (or crab boil). I put the spice in a large tea ball because we don't happen to like crunching whole spices--some people do. Keep at a gentle simmer for 4 or 5 hours, or until very tender. Remove the meat from the pot, add carrots and parsnips (and white potatoes if you eat them). Cook 10 minutes or so then add wedges of cabbage. Cook until the cabbage is done and serve with mustard or horseradish. Leftovers can be made into corned beef hash using the leftover carrots and parsnips instead of potatoes (or in addition to potatoes).