In a pot, bring 3 cups of water to boil. Then add a big handful of shrimp/prawn heads. Boil the shrimp head until the water turns slightly orange in color.

Press the shrimp heads with spatula to extract the “goodies” from their heads. Let the stock reduce to slightly more than 2 1/2 cups.

Drain the shrimp stock and discard the shrimp heads.

Add lemongrass, galangal, kaffir lime leaves, bird’s eye chilies, mushrooms, nam prik bao to the shrimp stock and bring it to boil.

Add in the shrimp and fish sauce.

Lastly, add the lime juice and tomato(if you add lime juice too early, the soup might turn bitter).

Boil until the shrimps are cooked, dish out and serve hot.

DONE!