Mix salt and pepper and apply brisket rub liberally to the entire brisket.
Preheat smoker to 300°F.
Place brisket fat side down on the grates and close the lid. Cook for 2 hours.
Remove brisket from the smoker and wrap in a double layer of foil. Before sealing the foil shut, spritz the brisket with a little bit of apple cider vinegar.
Tightly wrap brisket in foil and place it back on the smoker.
Insert probe meat thermometer (through the foil pack is ok) into the center of the brisket.
Cook for about 3 more hours, or until internal temperature of the brisket reaches 203°F.
Once the brisket reaches 203°F, remove it from the smoker. Open the foil slightly to allow it to vent for about 5 minutes.
Close the foil and allow the brisket to rest fully wrapped for 45 minutes.