Step 1The day before cooking, rub both sides of the brisket with the Liquid Smoke. Combine the salt, sugar and 2 tablespoons chile power in small bowl and spread half over the fattier side of meat, patting it into meat. Lay the brisket in a large glass baking dish, seasoned side down, and spread the remaining salt mixture over the top side. Cover and refrigerate 24 hours.
Step 2Heat the oven to 325 degrees. Brush the bottom of a roasting pan with oil and pour in the beef broth. Remove the meat from the dish and place it in the roasting pan fat side up. Pour any liquid left in the dish over the brisket. Cover tightly with foil. Roast 3 1/2 to 4 hours altogether, checking at 2 hours to make sure there is enough liquid to cover the bottom on the pan. If necessary, add beef broth. Continue to roast and check every 30 minutes, adding broth as needed until the meat is falling-apart tender.
Step 3While the meat cooks, combine the ketchup, vinegar, sugar, Worcestershire sauce and the remaining 4 tablespoons chile powder in large deep saucepan with one-half cup water. Bring to a boil, stirring often, then reduce heat to a simmer and cook 30 minutes, stirring occasionally to prevent scorching.
Step 4Remove the brisket from the oven and drain off the fatty liquid. Slice the meat and arrange on a serving platter with the sauce or offer the sauce on the side.