This Vietnamese chicken curry soup (Ca Ri Ga) is made with madras curry powder, lemongrass, and coconut milk. The addition of coconut water makes it lighter while still maintaining a rich flavored broth.
For the lemongrass, remove the tough, woody outer layer and mince the white and light green parts.
Grind the minced lemongrass and garlic cloves with a mortar and pestle until grounded into a paste.
Put chicken pieces in a large mixing bowl. Add lemongrass and garlic paste, finely minced onion (or shallot), madras curry powder, and fish sauce. Toss the chicken to coat well. Marinate the chicken for at least 30 minutes to overnight.
Heat oil in a pot over medium high heat, brown chicken on all sides in small batches without crowding too much.
When all the chicken pieces are browned, add coconut water, chicken stock, and sugar to the pot. Bring to boil and reduce the heat to medium low. Cover the pot with a lid and simmer for 15-20 minutes
Add potato and carrot pieces and continue to cook, covered, until they are tender and soft over medium heat, about 10 minutes. Add coconut milk and heat through, about 3-4 minutes.
To serve, ladle the hot curry into individual serving bowls. This curry soup is traditionally dipped with a Vietnamese baguette (banh mi) or use a French baguette. It is also great over rice noodles or vermicelli.