Cut the pork leg into desired sizes, wash thoroughly, and let it drain.

Bring water to a boil and add the Tom Yum ingredients: galangal, lemongrass, kaffir lime leaves, salt, and soy sauce. Wait for it to boil.

Once boiling, add the pork leg without stirring. Wait for it to boil again, skim off any foam, and then reduce the heat to low. Simmer until the meat is tender to your liking (you can stir after it boils).

Pound the bird's eye chilies, fish sauce, lime juice, and seasoning powder (if desired) in a bowl.

Ladle the Tom Yum into the bowl and adjust the taste as you like. Sprinkle with sliced herbs.

Note: If you want to add mushrooms, add them 3 minutes before turning off the heat after the pork leg is tender.