Place the stock into a large pot over high heat and bring to a boil.
5 cups chicken stock
Add the lemongrass, tomatoes, ginger, and red chilies. Return to a boil, reduce heat and simmer for 15 minutes.
2 stalks lemongrass, 2 tomatoes, 2 tablespoons ginger, 2 Thai red chili peppers
Add the fish sauce, sugar, shrimp, mushrooms, and lime juice and cook for another 3 minutes, or until the shrimp and mushrooms are cooked through.
2 teaspoons fish sauce, 1 teaspoon sugar, 12 shrimp, 1 cup mushrooms, 1 lime
To serve, pour the soup into four bowls and put a couple of the shrimps on a mini skewer in each bowl. Garnish with basil and cilantro. Add soy sauce to taste.
Notes
You can refrigerate this soup in an airtight container for up to 4 days. Do not leave it out at room temperature for more than 2 hours.
Reheat it on the stove to a rolling boil for food safety purposes.