In a medium saucepan place the fish sauce, water, lime juice, ginger, sugar, coconut milk and lemongrass.
Bring to a boil and simmer over medium heat for 20 minutes.
Add the mushrooms, meat or tofu, and chili paste. Simmer 15 minutes.
Ladle into bowls and garnish with cilantro.
I LOVE THIS SOUP! :) Thanks!