Authentic Tom Kha Gai (Thai Coconut Chicken Soup)

In a small bowl, combine the sliced chicken thighs with cornstarch, 2 teaspoons of neutral oil, and 2 teaspoons of fish sauce. Toss well to coat and set aside to marinate while you prepare the soup base.

Place a medium soup pot over medium-high heat and add the remaining 1 tablespoon of oil. Add the mushrooms and sauté for about 5 minutes until they are tender and lightly browned. Pour in the chicken stock and add the lemongrass, galangal, lime leaves (or zest), Thai chilies, red curry paste, and palm sugar. Bring the mixture to a boil, then reduce the heat, cover, and simmer for 6 minutes to allow the aromatics to infuse the broth.

Stir in the coconut milk and bring the soup back to a gentle simmer over medium-high heat. Watch the pot closely and avoid a rolling boil, as high heat can cause the coconut milk to separate. Add the marinated chicken to the pot. Once it returns to a simmer, lower the heat to medium-low, cover, and cook for about 8 minutes until the chicken is fully cooked through.

Turn off the heat and stir in the remaining fish sauce, lime juice, and fresh cilantro. Taste the broth and add a pinch of salt if needed. Ladle the soup into bowls and serve immediately on its own or with a side of steamed jasmine rice.