Remove the brisket from the fridge and bring to room temperature.
Meanwhile, prepare the smoker for smoking and bring the temperature to 225°F. Make sure there is enough charcoal and wood chunks (hickory is great for this) to cook the brisket.
Trim excess fat with sharp knife or fat trimmer until there it’s about ¼” thick.
Slather the brisket with yellow mustard and sprinkle with salt, pepper, and garlic powder.
Cover the brisket with a heavy coating of rub and let sit for 30 minutes (we used Texas rub on this one!)
Place the brisket in the smoker fat side up. Smoke until the internal temperature reaches 190°F on a digital thermometer. This will take approximately 1 ½ hours per pound, so about 15 hours for a 10 pound brisket, with a few steps before it reaches the final temperature.
At about the halfway point of cooking (after about 7-8 hours), spray the brisket all over with apple juice. Wrap it up tightly and continue to smoke the brisket. Make sure there is enough charcoal and wood chunks to continue cooking the brisket.
When there is about 30 minutes left, coat the brisket with barbecue sauce, wrap tightly, and smoke the brisket until it reaches the final temperature of 190°F on a digital thermometer.
Remove from smoker and coat the brisket with a final coating of barbecue sauce. Double wrap in foil and a blanket or towel. Allow the brisket rest for at least one hour before serving. Slice against the grain. Serve with extra barbecue sauce.