01 - Pat the brisket dry with paper towels. In a small bowl, combine salt, pepper, smoked paprika, garlic powder, onion powder, and cayenne (if using). Rub the spice mix evenly over the entire brisket.
02 - Heat olive oil in a large skillet over medium-high heat. Sear the brisket on all sides until browned, approximately 2–3 minutes per side to develop a flavorful crust.
03 - Transfer the seared brisket to a slow cooker, fat-side up.
04 - In a mixing bowl, whisk together ketchup, apple cider vinegar, brown sugar, Worcestershire sauce, Dijon mustard, smoked paprika, garlic powder, onion powder, black pepper, and sea salt until smooth and well combined.
05 - Pour half of the BBQ sauce over the brisket in the slow cooker, reserving the remaining sauce for serving.
06 - Cover and cook on LOW for 8 hours (or HIGH for 4–5 hours), until the beef is very tender and shreds easily with a fork.
07 - Transfer brisket to a cutting board. Let rest for 10 minutes to allow juices to redistribute.
08 - Slice or shred the brisket against the grain. Skim excess fat from the slow cooker sauce, then return the sliced or shredded brisket to the sauce, tossing to coat evenly.
09 - Serve hot with reserved BBQ sauce on the side.