Step 1

Cook noodles according to package directions; drain.

Step 2

Meanwhile, in a large saucepan combine broth, fish sauce, cinnamon, ginger, and, if desired, star anise. Bring to boiling; reduce heat. Simmer, covered, for 5 minutes. Add green onions; simmer, uncovered, for 5 minutes. Add chicken; simmer, uncovered, for 1 minute more. Remove and discard cinnamon and star anise.

Step 3

Divide cooked noodles among soup bowls. Ladle broth mixture over noodles. Serve with bok choy (if desired), herbs, jalapeño peppers (if desired), and lime wedges.