Have you ever heard the term "same same, but different"? Well, if you've ever traveled throughout Southeast Asia, then we bet you our last jar of nut-butter that you know exactly what we’re talking about. We slurped down many bowls of Tom Yum soup when travelling through Thailand. At first, soup felt like an odd choice when you’re soaking through your t-shirt with sweat. But once we got started, we couldn’t stop. Traditionally, Tom Yum (or Tom Yam) soup is studded with lemongrass, galangal, bird’s eye chili, fish sauce, and a protein like shrimp. It has an amazing balance of spicy, sour, sweet, and umami notes. This vegan version is not traditional, but it’s a delicious twist that still brings back some of the memories of eating and cooking our way through Thailand. It’s one of those “same same, but different” moments.
We swapped out a few traditional ingredients for ones carried by most grocery stores. Traditionally, galangal would be used instead of ginger (galangal has slightly more peppery notes). But ginger works well here. We swapped lime leaves for a combination of fresh lime zest and juice added at the end. And to keep things vegan, we use tamari for a bit of umami boost, in absence of the fish sauce. If you can find galangal and lime leaves, we encourage you to check out this vegan Tom Yum Soup recipe.
The base of this soup is an aromatic mix of lemongrass, onion, garlic and ginger. Tom Yum soup has an amazing balance of flavors, something the sweet ladies at Thai Farm Cooking School, demonstrated to us many years ago. For this version, we season the broth with bird’s eye chili peppers (for spice), tamari or soy sauce (for salt and umami), fresh lime (for sour), and a tiny bit of sugar (for balance). Trust us when we say that all of these make the soup better, even though it might seem like a tiny amount for each. Also, a word of warning on spice. It’s a lot easier to add more in than to take it out. We like spicy, so we use two whole bird’s eye chili peppers, sliced thinly. But if you want less spice, start with one and remove the seeds. You can always add more at the end.
To give this soup a bit more heft, we often find ourselves adding rice noodles and tofu that we’ve shredded on a box grater. The tofu trick is handy for quickly adding a protein-boost to soups. The shredded tofu mingles in the background, and because it’s thin, it feels like it absorbs some of the flavors of the soup. Even my carnivorous mother loves it ("it reminds me of shredded chicken, in a good way!"). Thanks mom. If tofu just isn’t your thing, just leave it out. If we have some greens to use up (like spinach), we’ll toss those in too, but it’s entirely optional so freestyle this part however you see fit.
When serving to a crowd, we like to dish up the broth and noodles individually, and allow everyone to pile on extra toppings as desired. Usually we'll serve some extra sliced limes, thai basil, cilantro and chili peppers on the side. Leftovers stock keeps well in the fridge, but make the noodles fresh right before serving.
Thai Hot and Sour Soup
- 4 stalks lemongrass
- 1 tablespoon grapeseed oil (or other neutral oil)
- 1 white onion, diced (about 2 cups)
- 3 cloves garlic minced
- 1 tablespoon minced ginger
- 8 cups vegetable broth
- 1 to 2 Thai red chili, seeds removed and thinly sliced (see note 1)
- 12 oz extra-firm tofu
- 1½ cups sliced cremini mushrooms
- 3 tomatoes, diced
- Zest from 1 lime
- Juice from 2 limes
- 2 tablespoons tamari (or soy sauce)
- 1 tablespoon coconut sugar (or cane sugar, granulated sugar)
- ½ cup lightly packed Thai basil leaves (extra for garnish, see note 2)
- 2 cups baby spinach (optional)
- Cooked rice noodles (optional, see note 3)
- Lime wedges (for squeezing)
- Prep lemongrass: Trim 1-inch off both sides of the lemongrass. Use the back of your knife to pound each stalk (this helps release the oils). Cut each stalk into 3-inch lengths.
- Cook soup: Heat oil in a Dutch oven over medium heat. Add lemongrass, sauté until fragrant, about 3 minutes. Add onion, sauté until translucent, about 5 minutes. Add garlic and ginger, and stir constantly until fragrant, about 1 minute (be careful not to let garlic burn).
- Simmer: Add vegetable broth and chili. Cover with a lid and bring to a boil. Reduce heat to medium-low and simmer for 25 to 30 minutes to let the flavors develop.
- Grate tofu: Meanwhile, shred tofu on the large holes of a box grater.
- Strain broth: Strain broth using a fine-mesh sieve or strainer. Return strained broth to the pot over medium heat. Stir in mushrooms, tomatoes, and tofu. Cover with a lid and cook until mushrooms are soft, about 5 minutes.
- Season: Stir in lime zest and juice, tamari, and sugar. Taste and adjust seasonings as desired (tamari for salt, chili for spice, lime for sour, sugar for balance). Stir in Thai basil and spinach (if using).
- Serve: If using rice noodles, divide them into bowls. Ladle soup into bowls. Top with more Thai basil and serve with lime wedges for squeezing.
- Thai red chili: These chilis are very hot. It's easier to add spice rather than take it away, so start with a small amount and build up from there.
- Thai basil: It has slightly purple stems and a distinctly different taste than sweet basil. You can find Thai basil at well-stocked grocery stores or Asian markets. Don't substitute with sweet (Italian) basil.
- Noodles: I like to use medium-wide (Pad-Thai style) rice noodles here, but choose your favorite. Rice noodles cook quickly and are best served immediately, so cook them right before serving.