Prepare noodles – Cook according to package instructions; drain and set aside.
Toast spices – Heat oil; toast star anise and cinnamon for 2 minutes until fragrant.
Sauté aromatics – Add ginger and garlic; cook until lightly browned.
Build broth – Add chicken stock, fish sauce, soy sauce, lemongrass, jalapeño, and shrimp shells. Simmer 10–15 minutes.
Strain – Remove shells and spices for a clear golden broth.
Add shrimp and bok choy – Simmer until shrimp turns pink, 2 minutes.
Finish – Stir in lime juice and cilantro. Serve hot over noodles.
Garnish – Add fresh jalapeño and herbs before serving.
