1. Stir together first 4 ingredients and, if desired, liquid smoke in a large roasting pan. Place brisket in pan, fat side up. Spoon liquid over brisket. Cover tightly with aluminum foil, and chill 24 hours.
2. Preheat oven to 300°. Bake brisket, covered, 4 to 4 1/2 hours or until fork-tender. Uncover and let stand 20 minutes.
3. Transfer brisket to a cutting board. Trim fat from brisket. Cut brisket across the grain into thin slices. (Or cut brisket into large pieces, and shred with two forks.) Pour pan drippings through a wire-mesh strainer, discarding solids. Serve brisket with drippings. Garnish, if desired.