Preheat your smoker to 225°F using oak or hickory wood for an authentic Texas profile.
Trim the beef brisket flat of excess surface fat, leaving about a quarter-inch layer to maintain moisture during the long cook.
In a small bowl, combine the sea salt, black pepper, garlic powder, and onion powder to create a dry rub.
Apply the rub generously to all sides of the brisket, pressing it firmly into the meat.
Place the brisket in the smoker and cook until the internal temperature reaches 165°F and a dark bark has formed.
Wrap the brisket tightly in butcher paper and return it to the smoker until the internal temperature reaches 203°F.
Remove the brisket and let it rest in a cooler or warm oven for at least 60 minutes to allow the juices to redistribute.
While the meat rests, thinly shred the cabbage and toss it with apple cider vinegar, honey, and mustard seeds.
Slice the brisket against the grain into thin strips and serve with the fresh slaw and pickles.