How to Make It
Combine first 5 ingredients and, if desired, lemon grass and kaffir lime leaves in a large saucepan over medium-high heat. Bring to a boil; reduce heat, and simmer 10 minutes. Stir in lime juice. Add shrimp, and simmer 10 more minutes. Discard ginger and lemon grass. Stir in sliced mushrooms and cilantro.