Combine the chipotle powder, onion salt, celery salt, and black pepper in a small bowl to create your dry rub. Pat the brisket completely dry with paper towels—this helps the spice rub adhere better and allows for better browning. Generously rub the entire brisket with the spice mixture, coating all sides evenly. Wrap the seasoned brisket tightly in foil, creating a tent that allows some air circulation. Refrigerate overnight (or at least 8 hours) to allow the flavors to penetrate the meat.

While the brisket is chilling or after removing it from the fridge, combine the BBQ sauce, 2 tablespoons chipotle powder, and 3 tablespoons fresh lime juice in a bowl. I like to whisk this together thoroughly so the chipotle powder fully dissolves and distributes evenly—this creates a more complex, smoky-spicy flavor than store-bought sauce alone. Set this sauce aside; you'll use it during the final stages of cooking.

Remove the brisket from the refrigerator 45 minutes before cooking to bring it closer to room temperature—this ensures more even cooking throughout. Preheat your oven to 300°F. Place the foil-wrapped brisket on a large baking sheet or roasting pan and bake for 3 hours. After 3 hours, carefully unwrap the foil, brush the meat generously with the chipotle-lime BBQ sauce from Step 2, then re-wrap the foil around it. Continue baking until the brisket reaches an internal temperature of 185°F (about 1-1.5 hours more, depending on thickness). This low-and-slow method renders the fat and connective tissue, creating incredibly tender meat.

Once the brisket reaches 185°F internal temperature, remove it from the foil and place it directly on a foil-lined pan. Brush the top with any remaining sauce and place under the broiler for 2-3 minutes, watching closely to develop a caramelized, slightly charred crust without burning. This step adds textural contrast and deepens the flavors with a little char.

Transfer the brisket to a cutting board, tent loosely with foil, and let it rest for 20-25 minutes. This resting period allows the juices to redistribute throughout the meat, ensuring moist, tender slices. While the brisket rests, prepare all your bowl toppings: cook the rice according to package directions, chop the romaine into 1-inch ribbons, warm the black beans and corn, dice the tomato into 1/2-inch pieces, finely dice the red onion, slice the avocado, and have the sour cream, cilantro, lime wedges, and shredded cheese ready at hand.

Slice the rested brisket against the grain into 1/4-inch thick pieces—slicing against the grain is crucial for maximizing tenderness. Divide the cooked rice among serving bowls as your base, then layer with the romaine, black beans, corn, and tomato. Top each bowl with a generous portion of sliced brisket and arrange the avocado slices on top. Finish with a dollop of sour cream, a sprinkle of shredded cheese, fresh cilantro, and serve with lime wedges on the side for guests to squeeze over as desired.