The secret is to squeeze the leaves before cooking.
I do not know how long the sôn bush has been present in our back garden. Mom says no one has planted it; it has grown by itself. Season after season, it grows, dies, then grows again. It is as if it preoccupied that land, allowing no other plants to encroach.
Strangely enough, my house is the only one in the area that has the sôn bush. Neighbors often drop by, asking for some when they are too lazy to go picking it in the field. Just a handful is enough for a pot of sour soup. My Mom's soup tastes so good. My aunt from Sai Gon stayed with us for a couple of days but she soon got addicted to the soup. When returning to Sai Gon, she insisted on bringing back a plant.
It has been raining for many days on end; muddy water upstream is rushing down. The field is flooded and fish follows the water into the river. My eldest brother set up a net in the creek, collecting some small fish for Mom. As for the snakehead, as big as his wrist, he asked her to cook sour soup. Mom laughed, saying sour soup is not for cold days. But he insisted on his favorite. He put on the raincoat and ran out to the sôn bush, not forgetting to pick some culantro too to add flavors to the soup.
Sôn is a climbing vine with lots of thorns so one must pick it with care if one does not want to be pricked. Even buds are tough too, and one can pick the tender top only. A knife or scissors are needed. My brother is lazy. He once even used his mouth and his lips got hurt. Mom felt so sorry for him but said: "Shame on you."
Sôn leaves are five-lobed. Older leaves have more thorns; thus only tender leaves are used. Sôn tastes a bit sour. Sour soup with it is best with fish from the river such as crucian, goby, cranoglanis, etc. but best of all is with snakehead from the field.
Mom's sour soup is so simple to cook. After cleaned, the fish is sliced into pieces and soaked with spices for 15-20 minutes. Cut shallots into very thin slices; fry them with some oil then pour in the fish. Add a little water then cook on a small fire for about three minutes. Pour in about a bowl of water; wait until it boils then drop in the sôn leaves; add torn culantro and some pepper. Snakehead cooked with sôn tastes better than with fermented bamboo shoot, pineapple or tomatoes.
Mom's secret is to squeeze the leaves before cooking and adding in a deseeded red hot chili pepper. Good sour soup is a combination of tastes: sour, hot, salty and sweet. A good cook knows how to balance the tastes; too sour, too spicy, too salty or too sweet spoils the soup.
That is my Mom's recipe. It is still flooding; certainly the market is full of snakeheads from the field. If you want to try fish soup with sôn leaves, run to the market. If you cannot find sôn, then drop by my house; it is always available for you.
Story and photo: LINH CHI