Combine the olive oil, apple cider vinegar, liquid smoke, and bbq rub.
Once everything is mixed, rub it all over a 7-8lb beef brisket.
Next, spray the slow cooker with nonstick spray.
Place the beef brisket in the slow cooker.
Set the slow cooker on low and let cook for 12 hours.
Once done, carefully remove the brisket out of the slow cooker.
Place the brisket in a foil line baked dish.
Turn your oven on broil, then place the brisket in the oven. Let it stay in there long enough until the " bark" ( the rub) darkens.
Once done, remove the brisket out of the oven, and cover it with foil.
Let the brisket rest for 1 hour!
Serve and enjoy!