Trim fat off top of brisket but leave fat on the bottom.
Combine beef consommé, 6 ounces of cold water, Worcestershire sauce and soy sauce in a bowl and mix thoroughly.
Fill meat injector with mixture, and using a checkerboard pattern, inject every other square, alternating squares on each row.
Combine remaining mixture with 6 ounces of cold water and refrigerate.
Combine seasoning salt, white and brown sugars, garlic powder, cumin, chili powder and black pepper in a bowl to make a rub.
Apply a heavy coat of the rub to the meat and let meat rest for 30 minutes before cooking.
Preheat one zone on opposite side of grill that you will be cooking on to 225-250 degrees. (See note below.)
Place brisket on grill fat side down and cook until internal temperature reaches 160 degrees (3-5 hours depending on the size of the brisket.) One temperature is reached, remove from grill.
Layer two sheets of heavy duty foil (36 inches each) and place meat in middle. Fold up sides and lay the stick of Challenge Butter on top of the meat and pour on the remaining injection. Seal up remaining sides at the top and place back on the grill.
After 3 more hours, check internal temperature. Once it reaches 200-210, it is done. The longer brisket cooks, the more tender it will get. Once removed from the grill, let it rest in foil for a minimum of 30 minutes.
After resting, remove brisket from foil and cut off remaining fat. Sauce the meaty side of the brisket and slice across the grain rather than parallel.
If using a grill, you can add smoky flavor to your brisket by creating a pouch out of aluminum foil and filling with smoker chips. If using a charcoal grill, place chips directly under charcoal. If using an oven, place brisket in a pan.