01 - Preheat oven to 300°F (150°C).
02 - Combine kosher salt, black pepper, smoked paprika, brown sugar, garlic powder, onion powder, ground cumin, and chili powder in a small bowl to create a spice rub.
03 - Pat brisket dry with paper towels, then evenly coat all sides with the prepared spice rub.
04 - Place sliced onions, smashed garlic, and sliced carrots in the bottom of a large oven-safe roasting pan or Dutch oven.
05 - Set the seasoned brisket atop the vegetable bed, fat side facing upward.
06 - Mix beef broth, red wine (if used), and Worcestershire sauce in a measuring cup, then pour around but not over the brisket.
07 - Cover the pan tightly with aluminum foil or a lid to retain moisture and roast for 4 to 4½ hours, until the brisket is tender when pierced with a fork.
08 - Remove the brisket from the oven and let it rest, covered, for 20 minutes to retain juices before slicing.
09 - Slice the brisket against the grain and serve alongside the cooked vegetables and pan juices.