Vegetarian Tom Kha Soup With Corn & Sweet Potatoes

Put your late summer produce to work in this deliciously simple Vegetarian Tom Kha Gai Soup recipe! I’ve replaced the chicken (gai) with plenty of veggies but kept the dreamy coconut base for a fantastic fusion meal. Better yet, this naturally gluten-free Thai veg soup also happens to be vegan!

Do y'all have litmus tests for different restaurant cuisines? For me, it's tacos de lengua and enchiladas verdes at Mexican restaurants, pho tai and bi chay banh mi at Vietnamese spots, paneer tikka masala and pav bhaji at Indian restaurants. But at a Thai restaurant, it's always tom kha soup—even before I dive face-first into some yummy curry.

Anyway, Joe was craving Thai the other night. At the moment, I’m on another No-Spend Grocery Challenge, so I both needed to avoid eating out and use what I had on hand. Luckily, my CSA was popping this week. While a corn and sweet potato vegetarian tom kha is not something I had ever previously tasted, it was delicious. 

All of the flavors I'm used to in classic Thai coconut soup came through beautifully. It was lightly sweet from the corn and the sweet potatoes; spicy as a result of the ginger, peppers and Sambal Oelek; bright and fresh from the lime and lemongrass; salty and umami from the fish sauce. Even though it was far from traditional, it absolutely scratched our itch for Thai.

Jump to:

• What is Tom Kha Gai Soup?
• Why You’ll Love This Vegetarian Tom Kha Soup Recipe
• Ingredients & Substitutions
• How To Make Tom Kha Soup, Vegetarian-Style
• Optional Variations & Dietary Adaptations
• Expert Tips
• Storage and Reheating Instructions
• FAQs
• More Vegetarian & Vegan Recipes For Summer
• Vegetarian Tom Kha Soup with Corn and Sweet Potato
• 💬 Reviews

What is Tom Kha Gai Soup?

Tom kha gai is a beloved Thai soup that’s richly flavored with coconut milk, aromatics like chiles and garlic, brightly citrusy lemongrass, and packed with veggies and chicken. Translated to English, tom means “to boil,” kha means “galangal,” and gai means chicken. So, technically speaking “vegetarian tom kha gai” is an oxymoron. That said, vegan or vegetarian tom kha is totally a thing!

In this bastardized white girl version of vegetable tom kha soup, I’ve taken some liberties. First, galangal root and kaffir lime leaves aren’t readily available at any of my local grocery stores. Instead, I swap in minced ginger and lime juice for passable substitutes. Lemongrass is similarly difficult to source without driving across town, so I use dried ground lemongrass powder instead.

In addition, I’ve replaced the more traditional pulled chicken and mushrooms with corn, a variety of chiles, and tender chunks of sweet potato, using the scraps to make a homemade vegetable broth. The resulting quasi-Thai vegetable soup is a lovely fusion of tradition and CSA-meets-Tim Gunn’s “make it work” mentality—ideal for using up your seasonal bounty. 

Why You’ll Love This Vegetarian Tom Kha Soup Recipe

• No Specialty Stores Needed - If you want to make authentic Thai tom kha gai, you’ll need some traditional Thai ingredients that aren’t necessarily readily available. In my version, I use easy-to-source swaps that are probably already in your pantry.
• Quick & Easy - If your veggies are already chopped, this yummy vegetarian tom kha soup will be ready in just 30 minutes.
• Bright, Fresh, & Bursting With Flavor - This Thai veg soup hits all the flavor notes—sweet, sour, salty, spicy, and umami. Delightful!

Ingredients & Substitutions

Despite being packed to the brim with bold flavors, this simple vegan Thai soup requires just a few basics:

• Coconut Oil - Feel free to swap in the neutral-flavored oil of your choice. You can also use olive oil, though it'll add a distinct flavor you wouldn't necessarily find in classic Thai cuisine.
• Fresh Corn on the Cob - In summer, fresh corn is cheap! You can easily swap in frozen corn kernels, but then you’ll need veggie stock as your soup base.
• Jalapeño - Bird’s eye chiles are more traditional, but not as easy to source. Jalapeños are cheap and widely available, making them my go-to hot pepper!
• Mesilla Peppers - These long, wrinkly peppers were part of my summer haul, but you're welcome to use Thai chilies, more jalapeños, or any other hot peppers you like. For a milder take, try poblanos!
• Sweet Potatoes - I don’t usually peel my taters since the skins are loaded with fiber and nutrients (and I’m often too lazy). You’re welcome to peel them if you like, or just give them a good scrub before dicing. Yams also work.
• Yellow Onions - I generally keep red and yellow onions on hand, and I usually use yellow ones for soup. Feel free to use red onions, white onions, or shallots. 
• Garlic - I like to buy a Costco bag of peeled garlic and keep it in the freezer as a shortcut, but you can also use a jar of minced garlic or a tube of garlic paste.
• Fresh Ginger or Ginger Paste - If you're using fresh, you'll need roughly a 2-inch piece. Dried ground ginger can be used in a pinch.
• Water - For simmering with your veggie scraps to make corn broth. If possible, start with filtered water for the cleanest taste.
• Canned Coconut Milk & Coconut Cream - Full-fat canned coconut milk is already quite rich, but adding an extra dollop of coconut cream makes this vegan Thai soup extra indulgent. If you don’t want to buy a separate item, simply refrigerate a can of coconut milk; the cream will rise to the top. Alternatively, use all coconut milk.
• Sambal Oelek aka Chili Garlic Paste - This little green-lidded jar is always within arm’s reach in my kitchen. Red curry paste will also work, and is probably more traditional to boot.
• Vegan Fish Sauce - You're welcome to sub in any other vegan-friendly umami bomb like Yondu vegetable umami, Bragg’s liquid aminos, coconut aminos, or even just a hefty sprinkle of MSG oughta do the trick. If you’re not a strict vegetarian/vegan, regular fish sauce is great too!
• Fresh Lime Juice - A squeeze of fresh citrus helps reinforce the bright flavor we’d normally get from fresh lemongrass. To get the most juice from each one, firmly roll the fruit on your work surface for 10-15 seconds before slicing it open.
• Powdered Lemongrass - or 1-2 fresh lemongrass stalks, or 2 drops food grade lemongrass essential oil, In a pinch, lemon zest and lemon juice will do the trick.
• Fresh Cilantro, Green Onion, Lime Wedges & Sriracha - Fresh herbs, spring onions, and spicy sriracha help add color, spice, and freshness.

How To Make Tom Kha Soup, Vegetarian-Style

Step 1: Make Scrap Vegetable Stock. Bring corn cobs, pepper ends, and onion peels to simmer with water in a large pot. Allow to simmer until ready to use.

Step 2: Sauté Corn kernels with coconut oil over medium heat, adding kosher salt to taste. When they begin to soften, move on to the next step. 

Step 3: Add Onions & Peppers. Add the onions, jalapeños, and peppers to the soup pot. Stir occasionally until peppers are softened and corn is beginning to turn golden. 

Step 4: Add Sweet Potatoes, stirring to coat, then add garlic, ginger, and lemongrass powder, stirring until fragrant.

Step 5: Stir in the coconut cream and coconut milk. Strain the veggie broth, and use enough to give the soup an appropriate consistency for your taste. Any broth leftovers can be frozen for up to 6 months.

Step 6: Simmer until sweet potatoes are fork-tender.

Step 7: Season with Sambal Oelek, lime juice, and fish sauce. (If you are using lemongrass essential oil add it here). Adjust the flavors as necessary. Season with kosher salt to taste.

Step 8: Garnish & Serve. Divide into bowls and top with garnishes of choice. Enjoy!

Optional Variations & Dietary Adaptations

• Vegan Tom Kha Gai. This veg tom kha recipe omits any meat substitutes in favor of summer produce. If you want to replace the gai (chicken) with a plant-based alternative, Butler’s soy curls are my favorite! Simply rehydrate them in vegan chicken broth before adding to the soup in the last few minutes of simmering.
• Tom Kha Tofu. For more protein that isn’t masquerading as meat, press a block of firm or extra firm tofu, cut into 1-inch cubes, and add to the soup in the last few minutes of simmering the sweet potatoes in Step 6. 
• Lighter. Use a heart-healthy liquid oil (e.g. avocado) in place of the coconut oil, and use full fat coconut milk instead of coconut cream. If you'd like to go a step further, you can use light coconut milk, but make sure to keep the full-fat version as your cream replacer.
• Sweeter. I think the corn, sweet potatoes, and coconut give this sweet n' sour soup plenty of depth of flavor. That said, if you'd like to sweeten the pot, you can add a teaspoon or two of brown sugar, coconut sugar, or palm sugar (jaggery).
• Add-Ins. Feel free to use this creamy soup recipe as a template. You can replace or add whatever veggies you have in the crisper drawer—red bell pepper, bok choy, bamboo shoots, oyster mushrooms or shiitake mushrooms would all be lovely. You're also welcome to add some carbs for heft—serve it over a bed of steamed jasmine rice or add a handful of rice noodles. 
• Shortcut. If you don’t have time to prep all the veggies for this vegetarian Thai tom kha soup, just raid the frozen aisle! Chopped onions, sweet potatoes, and corn kernels are readily available. Tubes of jalapeño paste or other spicy green chiles can often be found near the ginger and garlic paste to eliminate another step. Then, just use any vegetable broth or bouillon you like.

Expert Tips

• Ginger Paste in a tube is one of my favorite things to keep in stock. It's already peeled and minced down to perfect consistency and ready to squeeze into whatever dish you have on hand. It gives a more pungent and authentic gingery bite than dried ground ginger, and is much easier to sauté with the aromatics. From my experience it lasts upwards of a month—key if you want to avoid the grocery store.
• Pantry-Friendly Lemongrass. Here in the ‘burbs of Nashville, "lemongrass" means "asian supermarket." While I’ll make the 30-minute drive to K&S when I can, dried powdered lemongrass and food-grade lemongrass essential oil are excellent pantry-friendly substitutes. 
• The ONLY Bottled Lime Juice Worth A Darn. I know that what I'm about to write is kitchen sacrilege. Please forgive my transgression, but my refrigerator is never without a bottle of Nellie and Joe's Famous Key Lime Juice. I know, I know. Fresh citrus is best. But this bottle has saved my tushie more times than I can count. Not only is it an acceptable substitute for fresh citrus when cooking, it's also great for making my gluten-free key lime pie bars.  
• Reduce Waste, Increase Flavor! Save your scraps to make homemade veggie broth. Aromatic ingredients like ginger root peels, pepper heads, onion skins, and corn cobs are filled with flavor, so extract every last bit of goodness before tossing it in the compost pile.

Storage and Reheating Instructions

• As with most soups and stews, this vegan tom kha soup recipe is excellent for making ahead, as the flavors will continue to deepen after a day. 
• Refrigerating. Store in an airtight container in the fridge for up to a week. 
• Freezing. Unlike other creamy soup recipes, this coconut vegetable soup has no dairy, so it’s also an excellent candidate for freezing. Freeze leftovers in airtight containers with at least ½ inch of headroom for expansion, or use freezer-safe zip-top bags. Frozen tom kha soup will keep for up to 6 months.
• Heating. To serve, allow to defrost overnight in the fridge (if needed), then simmer over medium-low heat or microwave in 45-second bursts until warmed through.

FAQs

More Vegetarian & Vegan Recipes For Summer

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