Trim fat side of brisket to 1/4-1/2 inch thick. Wrap in butcher paper.
Mix dry rub ingredients in small bowl. Generously coat brisket on all sides. Wrap in plastic wrap. Let sit at room temperature for 1 hour.
Preheat Traeger grill to 225 degrees F. Place brisket on grill grate, fat side up. Close lid.
Cook for 3-4 hours or until internal temperature reaches 165 degrees F. Baste every hour with mop sauce made of equal parts apple cider vinegar and BBQ sauce.
When internal temperature reaches 195-205 degrees F, remove from grill. Double wrap in foil. Let rest for at least 1 hour or wrap in foil and towel and place in cooler for a few hours.
Slice against grain into thin slices. Serve with favorite sides. Store leftovers in airtight container in refrigerator for up to 4 days or freezer for up to 3 months.
Notes
For best results, use a whole packer brisket with both flat cut and point. Trim excess fat and connective tissue from point.
To add extra moisture and flavor, add beef broth to foil packet and place on grill.
Be patient and resist the temptation to turn up heat or open lid too often. Low and slow cooking is key to a tender, juicy brisket.