01 - Mix smoked paprika, brown sugar, kosher salt, black pepper, garlic powder, onion powder, and cayenne pepper in a small bowl until well combined.
02 - Pat the brisket thoroughly dry with paper towels. Coat the entire surface with the dry rub mixture, pressing firmly to ensure it adheres to the meat.
03 - Place the seasoned brisket in the slow cooker with the fat side facing up.
04 - Whisk together ketchup, apple cider vinegar, brown sugar, Worcestershire sauce, Dijon mustard, smoked paprika, liquid smoke, garlic powder, and onion powder until smooth.
05 - Pour half the BBQ sauce over the brisket, reserving the remaining portion for serving. Cover and cook on low setting for 8 hours.
06 - Carefully transfer the cooked brisket to a cutting board and allow it to rest for 10 minutes before slicing.
07 - Slice the brisket against the grain into thin strips. Skim excess fat from the cooking juices and serve with the reserved BBQ sauce.