When travelling through Thailand, I slurped down more bowls of soup than I could count. And that’s saying something, given the weather was averaging 105°F / 40°C! Although my memories of this trip get fuzzier with each year, I still remember being amazed at how a single bowl of soup could pack so much flavor. I couldn’t get enough. And perhaps best of all, it isn’t as hard to make at home as you might think.
Tom Yum (or Tom Yam) soup is also known as Thai Hot & Sour Soup. There are two main types: one with a clear broth, and the other with added milk. Both are loaded with spicy and sour flavor, thanks to a handful of aromatics, chili and fresh lime juice. This recipe features a good splash of coconut milk, which rounds out the flavors and adds just a hint of vegan-friendly creaminess to the already flavorful broth. If coconut milk isn't your thing, leave it out, or check out this recipe instead. Yes, I really love Tom Yum soup. And while traditional Tom Yum uses shrimp or other meat, as you’ll see, you can coax out just as much flavor without it!
While this soup is by no means high maintenance, you’ll likely need to visit an Asian grocery store to pick up some of the ingredients. The lemongrass, galangal, and kaffir lime leaves are pretty integral to the flavor, so I don’t recommend skipping out on them. Thankfully, you can freeze extra galangal and kaffir lime leaves, in case you buy more than you need. Just make sure to store them in separate air tight bags and use within 1-2 months.
After many rounds of testing, I think the one specialty ingredient that you could swap out are the Thai red chili peppers (also known as Bird’s Eye Chilis). Although they’re readily available at most grocery stores, you can compensate by adding a bit more Sriracha at the end instead. If you can get ahold of them, I do recommend adding the finely diced Thai red chilis to the soup base, so that the spice can infuse as the soup cooks. These little peppers bring the heat, so to err on the safe side, the recipe calls for two peppers. You can add more spice at the end (if needed), but it's harder to go the other way around. Still, expect this soup to be spicy...otherwise calling it a Hot & Sour Soup would feel like a bit of a let down. Don’t you think?
Zucchini noodles make to this soup more substantial. They add freshness and crunch, and are a hassle-free way to pack in extra veggies. You can quickly spiralize the zucchini noodles while the soup boils, and then add the “zoodles” to each bowl before ladling the hot soup on top. Since it’s usually just the two of us, this recipe makes the perfect amount for our dinner and lunch the next day. Pro tip: Store extra zoodles in a mason jar, then pour in the reheated soup when you’re ready for lunch. It makes for a healthy, satisfying and delicious meal, no matter what!
Vegan Tom Yum Soup
- 4 stalks lemongrass
- 1 tablespoon grapeseed oil (or other neutral oil)
- 1 large yellow onion, diced (about 2 cups)
- 4 cloves garlic, minced
- 1 tablespoon minced galangal (see note 1)
- 6 cups vegetable broth
- 1 to 2 Thai red chilis, minced (see note 2 and note 3)
- 8 Makrut (Thai) lime leaves (center removed and thinly sliced, see note 4)
- 1¼ to 1½ lb zucchini
- 8 oz sliced cremini mushrooms
- 3 tomatoes, chopped
- ¼ cup lime juice (more if needed)
- 2 tablespoons tamari
- 1 tablespoon coconut sugar (or cane sugar or brown sugar)
- ¼ cup full-fat coconut milk (from a can)
- Sriracha (to taste)
- Scallions/green onions, thinly sliced (for garnish)
- Cilantro leaves (for garnish)
- Lime wedges (for serving)
- Prep lemongrass: Trim 1 to 2-inches (2.5 to 5 cm) off both ends of lemongrass stalk, and discard. Use the back of your knife to pound each stalk (this helps release the oils). Cut each stalk into about 3-inch (7 cm) lengths, then cut each piece in half lengthwise.
- Sauté aromatics: Heat oil in a large pot over medium-high heat. Add lemongrass and sauté, until fragrant, about 3 minutes. Add onion, sauté until golden at the edges, about 5 minutes. Add garlic and galangal, sauté, stirring constantly (so garlic doesn't burn), until fragrant, about 1 minute.
- Simmer: Add vegetable broth, chilis, and lime leaves. Cover with a lid and bring to a boil. Reduce heat to medium low, simmer to let the flavors infuse, 20 to 25 minutes.
- Make zucchini noodles: Meanwhile, use a spiralizer to make zucchini "noodles".
- Finish soup: Use tongs or a slotted spoon to remove lemongrass from soup. Add tomatoes and mushrooms. Simmer uncovered until the mushrooms have softened, about 5 minutes. Add lime juice, tamari, sugar and coconut milk. Stir to mix well. Taste and add Sriracha (about 1 tablespoon but adjust to taste) and more lime juice (if needed).
- Serve: Pile zucchini noodles into bowls. Ladle soup on top. Garnish with scallions, cilantro, and serve with lime wedges for squeezing.
- Galangal: Galangal root looks similar to fresh ginger, but it has smoother, paler skin. Galangal has a sharp citrusy flavor and is commonly used in Thai cooking. You can find galangal at Asian markets and well stocked grocery stores. Chop up any extra galangal and freeze for longer storage.
- Thai red chilis: There are many varieties of Thai red chilies. But most North American grocery stores sell just one type: small, about 2-inch (5 cm) long red chili with a curved tip at the end. While often generically (or inaccurately) labelled, they are often Jinda chili peppers (Prik Sod). These are the chili peppers we used to develop and test this recipe. Jinda chili peppers are slightly less spicy than Bird's Eye chili. Bird's Eye chili are shorter and less curved at the end. Just a heads up: we say "less spicy"...but for many people (including us), they're still super spicy! Use sparingly and add more if needed. We like spice and we only use 2 chilies for one batch (1x) of this recipe. You can freeze extra chilies for another use.
- Thai red chili substitute: If you can't find Thai red chilies or prefer milder spice, skip the chili and use more Sriracha for seasoning at the end.
- Lime leaves: Lime leaves impart a bright, citrus flavor. They can be found at Asian markets. Before using, remove the tough stalk that runs down the middle of the leaf. Use your knife to make two lengthwise cuts, on either side of the center stalk, then remove the stalk and thinly slice the leaves. For a visual example, this Saveur video (at 0:25-0:35) shows you how to cut away the stalk.