Heat oil in a large pot over medium heat. Add the shallots, ginger, garlic, lemongrass, and galangal slices. Sauté for about 2 minutes, until fragrant. Add the kaffir lime leaves and cook for another minute.
1 Tbsp shallots, 1 Tbsp ginger, 1 Tbsp garlic, 1 stalk lemongrass, 5 slices of galangal, 3-5 kaffir lime leaves
Pour in the chicken stock and bring to a boil over high heat. Reduce to a gentle simmer, cover, and cook for about 15 minutes to infuse the broth.
1.5 cup chicken stock
Remove and discard the galangal, lemongrass, and kaffir lime leaves.
Add the chicken, coconut milk, and remaining seasonings. Bring back to a gentle simmer over medium-low heat, cover, and cook for 15–20 minutes, until the chicken is fully cooked and tender.
2-3 pieces of chicken thigh, ⅔ cup coconut milk, ½ cup water, ½ tsp salt, 1 Tbsp fish sauce, ½ tsp palm sugar
Stir in the Thai chilis and mushrooms. Simmer for 2–3 minutes, then remove from heat and add in the lime juice.
½ Tbsp Thai chilis, ½ cup oyster mushrooms, 1 Tbsp lime juice
Taste and adjust seasoning with additional fish sauce or lime juice as needed before serving.