Directions

1. In a large pot heat broth over medium-high heat. Meanwhile, remove dried outer leaves from lemongrass stalks. Cut 3 pieces 2 inches long from the bottom of each stalk. Discard the upper two-thirds of stalks.
2. Add lemongrass pieces, ginger, chiles and lime zest to pot; bring to boiling. Reduce heat to medium-low; simmer 10 minutes. Strain broth; return broth to the pot.
3. Add lime juice, fish sauce (if desired), coconut milk and mushrooms; simmer 5 minutes. Add shrimp; simmer 3 to 4 minutes or until shrimp are pink and cooked through. Ladle soup into 4 warmed soup bowls, sprinkle with cilantro, and serve.