Remove Corned Beef from brine, rinse under cold water and dry with paper towels.
Place in the refrigerator uncovered for 30-45 minutes.
Preheat the smoker to 250 F.
Combine the spices for your rub together in a small bowl and season both sides of the beef brisket.
Add a few chunks of wood on the coals, then place the brisket in the smoker. Smoke until internal temp reaches 165 F, about 3 hours.
While brisket is cooking prepare the cabbage. Remove the center core of the cabbage. Add the butter to the interior of the cabbage and sprinkle 1 tablespoon of the seasoning rub. Wrap in foil, leaving the top of the cabbage exposed. Set aside until you wrap the brisket.
Wrap brisket with butcher paper and place back on the smoker and cook until internal temperature reaches 200 F. About another 3-4 hours. Add the cabbage to the smoker at this time.
Check the cabbage after 2 hours, you may need to wrap the top to prevent it from drying out.
Remove bith the cabbage and the brisket from smoker and place in a cooler to rest for at least 30 minutes.