Select a Prime grade whole packer brisket weighing 12-16 pounds with thick flat (2+ inches) and good marbling throughout.
Trim hard white fat between point and flat. Trim fat cap to 1/4 inch thickness. Score fat cap in diagonal criss-cross pattern with 1-inch spacing.
Prepare injection: Mix 1 cup beef broth, 2 tablespoons beef bouillon, 1 teaspoon white pepper, 1 teaspoon garlic powder, and 1 teaspoon onion powder.
Inject brisket in 1-inch grid pattern across flat and point, inserting at angles to distribute evenly.
Apply yellow mustard as binder. Mix 1 cup kosher salt with 1 cup 16-mesh black pepper. Pat (don't rub) seasoning onto all surfaces.
Refrigerate seasoned brisket for 1-3 hours until internal temperature drops to 40-45°F.
Preheat smoker to 180°F. Place cold brisket on grates fat-side up (offset) or per manufacturer recommendations (pellet).
Smoke at 180°F for exactly 1 hour for maximum smoke penetration.
Increase temperature to 225°F. Add water pan to cook chamber. Maintain 225-250°F throughout cook.
Starting at 2.5 hours, spritz with 50/50 apple juice and water mixture every hour.
When internal temperature reaches 165°F and bark is dark, wrap in pink butcher paper. Alternatively, wrap in double-layer foil at 160°F with 1/2 cup beef broth.
Continue cooking wrapped until internal temperature reaches 195°F, then begin probe testing.
Test probe tenderness by inserting thermometer probe into thickest part of flat. When probe slides through with butter-like resistance, brisket is done (typically 200-205°F).
Remove from smoker and rest wrapped in dry cooler or cambro for minimum 1 hour, preferably 2-4 hours.
Separate point from flat by following fat seam. Slice flat into pencil-thick slices (1/4 inch) against the grain.
Rotate point 90 degrees and slice slightly thicker (3/8 inch) to maintain structure.
For competition: Paint slices with strained au jus, dust with powdered rub blend. Keep slices touching until service.