Preheat oven to 350º. Make a dry rub by combining chili powder, salt, garlic and onion powders, black pepper, sugar, dry mustard and bay leaf. Season the raw brisket on both sides with the rub. Place in a roasting pan and roast uncovered for 1 hour.
Add beef stock and enough water to yield about 1/2” of liquid in the roasting pan. Lower oven to 300º, cover pan tightly and continue to cook for 3 hours, or until fork tender. Trim the fat and slice meat thinly across the grain. Top with juice from the pan.