Preheat your oven to 300°F.
Pat the brisket dry with paper towels and place it on a large cutting board. Rub the olive oil all over the brisket.
In a small bowl, combine the kosher salt, black pepper, garlic powder, onion powder, smoked paprika, and dried thyme. Rub this spice mixture evenly over the brisket.
In a large oven-safe roasting pan, spread the sliced onion and minced garlic evenly across the bottom. Place the seasoned brisket on top of the onions.
Pour the beef broth and Worcestershire sauce around the brisket in the pan, being careful not to wash off the seasoning.
Cover the roasting pan tightly with aluminum foil and place it in the preheated oven. Roast for about 3 to 4 hours, or until the brisket is fork-tender.
Remove the foil during the last 30 minutes of cooking to allow the brisket to brown slightly.
Once done, remove the brisket from the oven and let it rest for 15 to 20 minutes before slicing against the grain.