Thai Hot & Sour Soup

I don't know where I got this recipe originally, the card is all splattered and dirty. I wanted to post it here before I lose it.

• Ready In: 50 mins
• Serves: 4-8
• Yields: 8 cups

Ingredients

• 8  cups  chicken stock
• 3  stalks lemongrass, cut in 1 inch lengths
• 4  kaffir lime leaves
• 1  teaspoon lime zest
• 2  green serrano chilies, slivered
• 2  lbs chicken (or mixture) or 2  lbs shrimp (or mixture) or 2  lbs tofu (or mixture)
• 1  tablespoon  thick coconut milk
• 2  limes, juice of
• 1  red serrano chilie, slivered
• 2  tablespoons cilantro, chopped
• 3  green onions, chopped

Directions

1. Heat the chicken stock in a large pot with the lemongrass, lime leaves, lime zest and green chiles. Bring to a boil, then cover, reduce the heat and simmer for 20 minutes.
2. Add the meat and/or tofu to the stock and simmer until the meat is done.
3. Turn off the heat and add the coconut milk and lime juice. Stir to blend.
4. Pour soup into a tureen or ladle into bowls and sprinkle with red chili, cilantro and green onions.
5. Adjust individual servings to taste with additional chili, cilantro, green onions, soy sauce. fish sauce or lime juice.