In a large pot, bring water to a boil. Add the chicken and reduce to a simmer. Cook until the chicken is fully cooked through. This will create a flavorful chicken broth, which will be the base of your soup. Remove the chicken and set it aside; keep the broth for later use.

Crush the dried chilies in a granite mortar and pestle (or use a food processor).

Add the galangal and garlic, pounding them into a fine, aromatic mixture.

Gradually add the shallots and finger roots, continuing to pound until it forms a smooth paste.

Pound the cooked chicken into the spice paste to shred it while coating it thoroughly with the herbs and spices.

Heat a pot over medium heat and add half of the coconut milk. Cook and stir regularly until the oil starts to separate and bubbles form.

Stir in the pounded red curry paste with shredded chicken and cook until fragrant.

Add the remaining coconut milk, chicken broth, white sugar, salt, fish sauce, and fermented fish sauce. Stir well and bring to a full boil.

Add the kaffir lime leaves and green onions, then remove the pot from heat.

Boil dry rice vermicelli noodles until soft but still al dente. Drain and rinse under cold water. Check the package for specific cooking times and instructions. If using fresh noodles, they don’t need cooking and can be added directly.

Place a portion of noodles in a serving bowl. Ladle some of the spicy chicken soup over the noodles and garnish with sliced green onions, fresh herbs, a lime wedge, and any other toppings you like (see garnishing options in notes).