Preheat your oven to 300 degrees Fahrenheit and line a small baking dish with parchment paper.
In a small bowl, combine the smoked paprika, garlic powder, onion powder, chili powder, sea salt, and black pepper to create a dry rub.
Rub the spice mixture evenly over all sides of the beef brisket, pressing it into the meat to ensure it adheres.
Place the brisket in the prepared dish, cover tightly with foil, and roast for 3 to 4 hours until the meat is tender and easily pierced with a fork.
While the meat rests, whisk together the tomato paste, apple cider vinegar, and yellow mustard in a small saucepan over low heat to create a clean BBQ glaze.
Thinly shred the green cabbage and toss it with the olive oil and a splash of vinegar for a simple, crunchy slaw.
Slice the rested brisket against the grain, drizzle with the warm BBQ glaze, and serve immediately alongside the fresh cabbage slaw.