Tom kha soup is the silky, fragrant Thai coconut chicken soup you order at restaurants and then dream about later. This slow cooker version gets you that same lemongrass-and-lime perfume with almost no hands-on work: dump, stir, walk away, and come back to a pot of creamy, gently spicy comfort.
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The trick is layering aromatics whole so they infuse slowly without turning bitter, then adding the delicate ingredients like lime juice and cilantro at the very end so they stay bright. Chicken thighs stay juicy through the long cook, and full-fat coconut milk keeps the broth rich instead of watery.
Serve it as a starter or make it a full meal with rice. It reheats beautifully, which makes it one of the best make-ahead soups for busy weeks.
Why You'll Love This Recipe
About the Ingredients
1 1/2 pounds (680g) boneless, skinless chicken thighs, cut into 1-inch pieces
Thighs stay juicy in the slow cooker where breast can dry out. If using breast, add it in the last 90 minutes of cooking.
2 cans (13.5 oz / 400ml each) full-fat coconut milk
Full-fat is essential for a creamy tom kha; light coconut milk tastes thin and can separate. Shake each can well before opening.
3 cups (720ml) low-sodium chicken broth
Use a good-quality broth since it forms the base of the soup. Vegetable broth works for a lighter, less meaty flavor.
3 stalks lemongrass, tough outer layers removed, cut into 2-inch pieces and bruised
Bruise with the back of a knife to release oils. If lemongrass is unavailable, use 2 tablespoons lemongrass paste stirred in at the end.
1 thumb-size piece (about 1 inch) fresh galangal or ginger, sliced into coins
Galangal is more floral and peppery; ginger is a fine supermarket substitute. Leave the slices large so they are easy to fish out.
5 makrut (kaffir) lime leaves, torn
Fresh or frozen leaves are best; dried work in a pinch but need double the amount. Tear them to release the citrus oils.
8 oz (225g) cremini mushrooms, sliced
Cremini add meaty texture; oyster or shiitake mushrooms are excellent swaps. Wipe clean rather than soaking so they don't get waterlogged.
1 medium red bell pepper, thinly sliced
Adds sweetness and color; a handful of cherry tomatoes tossed in at the end is a lovely alternative.
3 tablespoons fish sauce, plus more to taste
Fish sauce provides the salty umami backbone. Use soy sauce or tamari for a vegetarian version.
2 tablespoons freshly squeezed lime juice, plus more to taste
Add lime at the very end off the heat so the brightness survives. Bottled lime juice tastes flat here.
1 to 2 teaspoons Thai chili paste (nam prik pao) or sriracha, to taste
Adjust for heat; a pinch of red chili flakes works if you don't have chili paste. Start small and taste.
1/4 cup chopped fresh cilantro, plus sliced green onions, to serve
Stir herbs in after cooking to keep them fresh and green. Thai basil is a fragrant substitute.
Tips & Tricks
Don't boil the coconut milk
keep the slow cooker on Low so the soup simmers gently. A hard boil can make coconut milk look grainy and split.
Fish out the aromatics
lemongrass, galangal, and lime leaves are for flavor only and are tough to chew, so remove them before serving.
Season at the end
fish sauce and lime are added after cooking because long heat mutes their brightness. Taste and adjust right before serving.
Pro Tips
Step-by-Step Instructions
1. Layer the aromatics
Add the chicken broth, coconut milk, bruised lemongrass, galangal, torn lime leaves, and chicken thighs to the slow cooker. Stir gently so the chicken sits in the liquid.
2. Add vegetables and seasoning
Stir in the mushrooms, bell pepper, fish sauce, and chili paste. Cover and set the slow cooker to Low.
3. Slow cook gently
Cook on Low for 4 to 5 hours (or High for 2 1/2 to 3 hours) until the chicken is fork-tender and reaches 165F (74C) on an instant-read thermometer and the broth smells fragrant.
4. Remove the aromatics
Using tongs, fish out the lemongrass stalks, galangal coins, and lime leaves and discard them. Skim any excess fat from the surface if desired.
5. Brighten the soup
Turn the slow cooker off, then stir in the lime juice and taste. Add more fish sauce for salt or lime juice for tang, one teaspoon at a time.
6. Finish and serve
Ladle into bowls and top with fresh cilantro and sliced green onions. Serve hot with jasmine rice on the side if you like.
Delicious Variations
Shrimp tom kha
swap the chicken for 1 pound of raw shrimp added in the last 20 minutes on High until pink and curled.
Vegetarian tom kha
use vegetable broth and soy sauce instead of fish sauce, and add cubed firm tofu in the last hour.
Extra-spicy tom kha
double the chili paste and add sliced fresh Thai chilies with the aromatics for a bolder kick.
How to Store Slow Cooker Tom Kha Soup (Thai Coconut Chicken Soup)
Refrigerator
Store in an airtight container in the refrigerator for up to 4 days; the flavor deepens overnight.
Freezer
Freeze in portions for up to 2 months, though the coconut milk may separate slightly; whisk after reheating.
Reheating
Reheat gently on the stovetop over medium-low heat until steaming but not boiling, then add a squeeze of fresh lime.
Frequently Asked Questions
Q: Can I use chicken breast instead of thighs in tom kha soup?
Yes, but add it later so it doesn't dry out. Stir diced breast into the slow cooker in the last 90 minutes on Low, and check that it reaches 165F (74C).
Q: Is tom kha soup spicy?
Tom kha is usually mildly spicy and more aromatic than hot. The chili paste is adjustable, so start with 1 teaspoon and add more to taste.
Q: Can I make this tom kha soup vegetarian?
Yes, use vegetable broth, soy sauce or tamari instead of fish sauce, and add tofu or mushrooms for substance. The coconut milk and aromatics keep it rich and fragrant.
Q: What can I use instead of lemongrass and galangal?
Lemongrass paste and fresh ginger are the best easy substitutes. Use 2 tablespoons lemongrass paste and a 1-inch piece of sliced ginger, then remove the ginger before serving.
Q: How do I keep coconut milk from curdling in the slow cooker?
Cook on Low and avoid boiling, which is what causes separation. Stir gently and add acidic lime juice only at the end, off the heat.
If you make this slow cooker tom kha soup, I'd love to hear how it turned out! Leave a comment below with your favorite tweak, and pin the recipe for your next cozy soup night.
Slow Cooker Tom Kha Soup (Thai Coconut Chicken Soup)
This slow cooker tom kha soup simmers chicken in creamy coconut milk with lemongrass and lime for a cozy Thai bowl you can set and forget.
🧂 Ingredients
- 1 1/2 pounds (680g) boneless, skinless chicken thighs, cut into 1-inch pieces
- 2 cans (13.5 oz / 400ml each) full-fat coconut milk
- 3 cups (720ml) low-sodium chicken broth
- 3 stalks lemongrass, tough outer layers removed, cut into 2-inch pieces and bruised
- 1 thumb-size piece (about 1 inch) fresh galangal or ginger, sliced into coins
- 5 makrut (kaffir) lime leaves, torn
- 8 oz (225g) cremini mushrooms, sliced
- 1 medium red bell pepper, thinly sliced
- 3 tablespoons fish sauce, plus more to taste
- 2 tablespoons freshly squeezed lime juice, plus more to taste
- 1 to 2 teaspoons Thai chili paste (nam prik pao) or sriracha, to taste
- 1/4 cup chopped fresh cilantro, plus sliced green onions, to serve
📋 Instructions
- 1Layer the aromatics — Add the chicken broth, coconut milk, bruised lemongrass, galangal, torn lime leaves, and chicken thighs to the slow cooker. Stir gently so the chicken sits in the liquid.
- 2Add vegetables and seasoning — Stir in the mushrooms, bell pepper, fish sauce, and chili paste. Cover and set the slow cooker to Low.
- 3Slow cook gently — Cook on Low for 4 to 5 hours (or High for 2 1/2 to 3 hours) until the chicken is fork-tender and reaches 165F (74C) on an instant-read thermometer and the broth smells fragrant.
- 4Remove the aromatics — Using tongs, fish out the lemongrass stalks, galangal coins, and lime leaves and discard them. Skim any excess fat from the surface if desired.
- 5Brighten the soup — Turn the slow cooker off, then stir in the lime juice and taste. Add more fish sauce for salt or lime juice for tang, one teaspoon at a time.
- 6Finish and serve — Ladle into bowls and top with fresh cilantro and sliced green onions. Serve hot with jasmine rice on the side if you like.
