Editor's Note: Please say hello to Leela of the fine blog She Simmers to the Serious Eats family. A scholar of philology, history, linguistics, and all things culinary, she'll be stopping by every other week to share her love of Thai cuisine with us. Welcome Leela!
I'm convinced that Tom Yam should be one of the first, if not the first, recipes you begin with when learning to cook Thai. In addition to being ridiculously easy to make, it's a dish that captures the essence of Thai flavors.
Then again, it's also just as easy to destroy. Don't even think about using lemon rinds, lemon juice, or soy sauce as substitutes for lemongrass, lime juice, and fish sauce. Using dried herbs instead of fresh will also instantly turn a lovely pot of Tom Yam into a cauldron of herbal medicine.
In Thailand, while dishes like Pad Thai—that require so many ingredients your head starts spinning—are almost always left to the street food cooks, Tom Yam is rooted firmly in the home kitchen. This is what a mother makes with a plate of Thai omelet for dinner when the fridge is nearly bare. This is what a grandmother whips up during monsoon season for her grandchildren who want a soothing, familiar meal. It's what a father who only cooks once a decade, can make blindfolded.
Making Tom Yam is kind of like making tea. To make tea, you infuse warm water with tea leaves; to make Tom Yam, you infuse warm broth with fresh herbs.
Unlike red or green curry, where you can't figure out all the ingredients just by looking at the finished dish, Tom Yam fully declares its main herbal components in its bowl. You're looking at galangal, lemongrass, and kaffir lime leaves. They're not meant to be eaten—well, except for maybe a few paper-thin slices of young galangal—but they're not removed like you would a used bouquet garni or sachet of spices in Western dishes.
In general, there are two ways of making Tom Yam: one that's best for cuts of meat that take longer to cook (like bone-in chunks of chicken, oxtails, tough cuts of beef) and one for quick-cooking meats (e.g. bite-size chicken breast pieces, shrimp, seafood).
For meats that need more time, start with plain water and some fish sauce to season the meat as it it stews. Once the meat is tender, add the aromatics, then the seasonings go in last. A garnish of cilantro (or culantro) is the last touch.
For quicker-cooking meats, which are more commonly used for Tom Yam, you need a different approach. Since there's not much to work with in the collagen and umami department, start out by making your own broth. Simmer the chicken or pork bones in plain water until you extract every bit of flavor out of them, then strain the bones. Infuse the broth with the herbs, season it and cook the meat in this barely-simmering broth just until cooked through.
There are many variations of Tom Yam. I like mine plain with nothing but meat in herb-infused broth that's been seasoned very simply with fish sauce and lime juice and spiced with a few crushed fresh bird's eye chilies. This is different from the heavier, more complex restaurant variation loaded with ingredients such as Nam Prik Pao, which is what most people know and like.
Then we have a more recent variation that contains—gasp—milk (which brings us back to the tea comparison). It seemed weird at first but it has slowly grown on me. Or maybe I'm just succumbing to the pressure seeing how Bangkok can't get enough of it.
Here's a recipe for the creamy version of Tom Yam Kung.