Combine salt, pepper, cumin, chili powder, oregano, paprika, garlic and oil in a small bowl. Rub seasoning over the side of the beef without the fat cap and let sit for 20 minutes. Place the brisket, fat side up, in a roasting pan. Add the beef stock and beef, cover and braise in the oven for 3 ½ to 4 hours or until brisket can easily be shredded with a fork. Remove from oven. Skim fat from cooking liquid and reserve 1 cup.