Place corned beef in a large pot, along with the liquid and spices that accompanied it in the package, and cover with boiling water.

Bring back to a boil, lower the heat, cover partially, and simmer as slowly as possible for about 3 hours, or until very tender when tested with a fork.

Preheat oven to 350°F.

Mix marmalade, mustard and sugar in a bowl until well combined.

When meat is done, remove from pot and drain.

Place meat in ovenproof dish (spray the bottom) and pour marmalade mixture over it, coating thoroughly.

Bake for 30 minutes, uncovered, or until glaze is crisp and brown. (Mine had to go a few minutes more for the crispy coating — worth it!).

Serve hot or at room temperature.