Preheat your smoker to 225°F using oak or hickory wood for an authentic Texas flavor profile.
Trim the beef brisket of excess hard fat, leaving about a quarter-inch of the fat cap to keep the meat moist during the long cook.
In a small bowl, combine the first portions of sea salt, black pepper, garlic powder, and onion powder to create the dry rub.
Apply the rub generously to all sides of the brisket, pressing it into the meat to ensure it adheres properly.
Place the brisket in the smoker, fat side up, and smoke until the internal temperature reaches 165°F, which usually takes several hours.
Wrap the brisket tightly in butcher paper or foil to preserve moisture and return it to the smoker until the internal temperature reaches 202°F.
Remove the meat from the smoker and let it rest for at least 30 minutes to allow the juices to redistribute.
While the meat rests, prepare the slaw by whisking together the apple cider vinegar, olive oil, and the remaining salt and pepper in a large bowl.
Toss the shredded cabbage and carrots into the dressing until well-coated and crisp.
Slice the rested brisket against the grain into thin strips and serve immediately alongside the fresh slaw.