My Grandmother had the best corned beef recipe of all time. But I didn't have her recipe and I needed to come up with something that was equally good. Hers had a sweet orange glaze on it that was to die for. This is nothing like it. But after playing with it this has become a family favorite. A favorite of The Fireman's. Just recently I have acquired my Gram's recipe and will be making it soon. I know that tradionally Irish Corned Beef has no glaze but you cant tell my family that. They beat to their own drum as do I.

Twice Cooked Corned Beef
I've purchased the biggest roast I could.

Dump into the crockpot and if it includes spices in a packet, sprinkle over the roast. Place the roast fat side down.

Cook slowly in crock pot till just about perfect. Mine was three hours on high. You could put this in the crockpot in the morning and put on low. Just dont overcook. We are going to glaze it and stick it back into the oven.
Take out of the crockpot. Place in casserole pan
Cover with brown mustard.Dump brown sugar over mustard. Rub into meat.
(note, if I was to do it again, I would NOT cover it. I went after the sugary crust on the bottom.)
Stick into the oven for 20 minutes at 375 degrees.
Let sit a good ten minutes (oh I snuck pieces) so slicing is easier. If you are only using for sandwiches then refrigerate overnight before putting on a slicer, if your lucky enough to have a deli slicer. I have to do it slowly with a knife.