Taiwanese Beef Noodle Soup

Preparation Bring water, soy sauce, rice wine, brown sugar, ginger, white parts of scallion, garlic, cilantro stems, tangerine peel, star anise, and red pepper flakes to a boil in a 5- to 6-quart pot, then reduce heat and simmer, uncovered, 10 minutes. Add short ribs and gently simmer, covered, turning occasionally, until meat is very tender but not falling apart, 2 1/4 to 2 1/2 hours. Let meat stand in cooking liquid, uncovered, 1 hour. Transfer meat to a cutting board with tongs and discard bones and membranes, then cut meat across the grain into 1/2-inch-thick slices. 3Pour beef broth through a cheesecloth-lined sieve into a bowl and discard solids. Skim fat from cooking liquid and transfer liquid to a 3-quart saucepan. Add chicken broth and meat and reheat soup over moderately low heat. Meanwhile, cook noodles in a 6- to 8-quart pot of (unsalted) boiling water until tender, about 7 minutes (14 to 15 minutes for linguine). Drain noodles well in a colander and divide among 4 large soup bowls. Ladle broth over noodles and top with meat, scallion greens, bean sprouts, pickled mustard greens, cilantro sprigs, and red chile (if using). *Available at some Asian markets. **Available at some Asian markets and Uwajimaya (800-889-1928). Cooks' note:Meat and beef broth can be cooked and strained 3 days ahead. Cool completely, uncovered, then chill meat in broth, covered. Skim fat before adding chicken broth.