In a large mixing bowl, whisk together the coarse black pepper and kosher salt first. Add the brown sugar, paprika, garlic powder, and onion powder, whisking continuously until the mixture takes on a reddish-brown color.

Sprinkle in the chili powder, cayenne pepper, ground cumin, and dried oregano. Whisk everything together thoroughly until you can't see any streaks or clumps.

Pour your spice rub through a fine-mesh sieve to break up any stubborn clumps, especially from the brown sugar. Press any remaining lumps through with the back of a spoon.

Pat your brisket completely dry with paper towels. Apply the Texas brisket rub generously, using about 2 tablespoons per pound of meat. Start with the fat side, pressing the seasoning into every crevice and corner. Flip and coat the meat side thoroughly.

Wrap the seasoned brisket loosely in plastic wrap or place it uncovered in the refrigerator. Let it rest for at least 2 hours, though overnight produces even better flavor penetration.