8cupschicken stock(unsalted, homemade or store-bought)
2stalkslemongrass(or three smaller stalks)
4inchesgalangal(peeled and thinly sliced)
6lime leaves(also known as kaffir leaves; rinsed)
For the soup
1lbstraw mushrooms(or white button, or oyster mushrooms, cut into bite-size pieces)
1Tbspchile jam(homemade or store-bought, plus more to taste)
1/4cupfish sauce(plus more to taste)
3dried red chiles(broken in half and seeds reserved)
1lbshrimp(peeled and deveined, with heads and tails intact if desired)
4Tbsplime juice(plus more to taste)
1/4bunchfresh cilantro leaves(finely chopped)
4fresh bird’s eye chiles(stemmed and bruised; seeded and de-veined for less heat; whole or sliced on the diagonal)
Four lime leaves(optional, but they look good in a bowl; not to be eaten)
Four cilantro twigs(optional; one twig per bowl)
Preparing the ingredients
Prepare the lemongrass stalks by trimming off leafy parts and the root end, and removing the tough outer layers of the bulb. Cut the bulb portions into 3-inch pieces and smash them with a cast iron pan or the blunt edge of a heavy knife until they are bruised and (almost) split in half. If they split, it's fine.
Cut the shallot in half and smash with cast iron pan, until it's bruised and juices start running. Smash the lime leaves with a heavy object to get them bruised and aromatic.
Preparing the broth
In a medium saucepan, bring the stock to a boil over high heat. Add the lemongrass, galangal, lime leaves, and the shallot, turn down the heat to medium, and let the broth infuse for 5 minutes.
Using a perforated spoon, remove the lemongrass, galangal, lime leaves and the shallot.
Finish the soup
Turn the heat to high again and bring the broth to a boil. Stir in the chile jam, then add the mushrooms. Boil for one minute.
Add the fish sauce, dried red chiles and the shrimp, and cook until the shrimp are pink, opaque, and firm, no more than 1 minute. Remove from heat.
Stir in the lime juice. Taste for seasoning and correct if needed (by adding more fish sauce, lime juice and chile jam). You should taste the sour notes first, then salty, with mild sweetness from the chile jam.
Stir in the chopped cilantro, ladle into bowls, garnish with fresh Thai chiles (whole or sliced), as well as the optional cilantro twig and lime leaf per bowl, and serve hot.
Traditionally, this soup is salty and sour, with a little bit of sweetness. In this recipe, I toned down the salty and sour notes as we like it a lot more this way. If you want your tom yum soup to be more traditional, you can easily double the amounts of fish sauce and lime juice specified in the recipe. However, I encourage you to start off with the amounts in the recipe and then adjusting to taste.Chile jam will make the soup incredibly spicy if you add a little too much of it. I start off with one tablespoon and adjust as needed. You can even add more chile jam in individual bowls as needed for those who like very spicy food.Chile jam can be substituted with chile paste and one tablespoon of sugar (white or brown).