Preheat oven to 325˚F.
Submerge corned beef in cold water for 15 - 30 minutes. Drain and pat dry.
Place corned beef (fat side up) in a baking dish and add Guinness (or ginger ale) to the pan.
In a small bowl, stir together the seasoning packet, olive oil, brown sugar, mustard, vinegar and apricot jam. Smear this mixture onto the top of the corned beef.
Cover the beef tightly with parchment paper and cover the pan with foil. Bake for 3½ - 4 hours.
Remove from oven and allow the corned beef to rest for about 10 minutes before slicing.
Place the sliced meat back in the baking dish and bake at 350°F for 20 - 30 minutes to brown.
The soak in cold water before cooking: This helps remove the excess salt of the meat.
