Prepare the Dry Rub: In a bowl, combine brown sugar, sea salt, black pepper, garlic powder, onion powder, chili powder, smoked paprika, dried mustard, and dried thyme.

Season the Brisket: Trim any excess fat from the brisket. Rub the spice mixture thoroughly over the entire surface of the meat, ensuring even coverage on all sides.

Marinate: Wrap the seasoned brisket tightly in non-stick aluminum foil. Refrigerate for at least 3 hours, preferably overnight, to allow the flavors to penetrate the meat.

Bring to Room Temperature: Remove the brisket from the refrigerator about an hour before cooking to let it come to room temperature.

Preheat Oven: Set your oven to 275°F (135°C).

Roast the Brisket: Place the foil-wrapped brisket on a baking pan, preferably on a rack. Insert an oven-safe meat thermometer into the thickest part of the meat. Roast until the internal temperature reaches 175°F (79°C).

Uncover and Continue Roasting: Carefully open the foil to expose the brisket. Continue roasting until the internal temperature reaches between 195°F and 205°F (90°C to 96°C), which may take an additional 1 to 2 hours.

Rest the Meat: Remove the brisket from the oven and place it on a cutting board. Tent it loosely with foil and let it rest for at least 25 minutes to allow the juices to redistribute.

Slice and Serve: Slice the brisket against the grain into pencil-width slices. Serve with your choice of sides.