Trim the brisket fat to about 1/4-inch. Trim off any silverskin from the meat side of the brisket. Using a marinage injector, inject about 1/4-cupof the beef broth, about 1 ounce per pound of raw brisket, throughout the brisket. To inject the meat, insert the needle parallel to the meat grain in several locations, at least 1-inch apart, and back the needle out as the plunger is depressed.
Rub both sides with a light coating of oil to help the rub stick to the meat. Liberally sprinkle with the rub mixture, and massage into the meat. Refrigerate for 1 to 2 hours to let meat marinate.
Set up grill for indirect cooking, and preheat to 235 F.
Place meat on grill and close the grill. Let cook for 90 minutes then check on the meet. If needed, add more charcoal or smoking chips, if using. Flip the meat and close the grill, cook for another 90 minutes. Insert a probe thermometer into the deepest part of the meat. Once the meat reaches 150 F, remove from grill, otherwise add any additional fuel and let the brisket keep cooking. Cooking times will vary based on meat weight and heat of grill.
Once the meat reaches 150 F, usually 4 to 8 hours, remove the brisket from the grill and place it on a double layer of aluminum foil, large enough to seal the meat, Before sealing, pour 1/2-cup of beef broth around the sides of the meat, being careful not to wash off any rub crust. Tightly wrap in the aluminum foil. Place the meat back on the grill or place in a deep roasting pan and place in an indoor oven preheated to 225 F. Continue to cook until the internal temperature reaches 205 F, another 2 to 3 hours depending on size.
Let rest before slicing. Serve hot with barbecue sauce and your favorite sides. Serves 8 to 12 people, depending on the size of brisket and the size of appetite.