Tom kha gai is the soup that makes Thai takeout feel like a warm hug: coconut milk, lemongrass, galangal, and lime leaves simmered until the broth turns silky and fragrant, with tender chicken and mushrooms floating in every spoonful. The only problem is standing at the stove to babysit it. This slow cooker version solves that completely.
Advertisements1
Everything goes into the pot, the slow cooker does the work, and you finish it with lime juice and fish sauce right before serving so the broth stays bright instead of flat. It is a set-it-and-forget-it dinner that tastes like it came from your favorite Thai restaurant, and it reheats beautifully for lunches all week.
If you have never cooked with lemongrass or galangal, do not skip them. They are the backbone of tom kha, and the supermarket substitutions in the ingredient notes below will get you very close.
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 tender through a long cook; chicken breast works too but add it in the last 90 minutes. Buy thighs labeled 'boneless skinless' so you skip trimming.
8 ounces (225g) cremini mushrooms, sliced 1/4 inch thick
Cremini has more flavor than white buttons; oyster or shiitake mushrooms are excellent swaps and hold their shape even better.
1 medium yellow onion, thinly sliced
A sweet onion or two large shallots can replace it for a milder, more delicate broth.
3 stalks fresh lemongrass, tough outer layers removed, cut into 2-inch lengths and bruised
Bruise with the back of a knife to release the oils. If fresh is unavailable, use 3 tablespoons frozen lemongrass paste or 4 dried stalks soaked 10 minutes.
5 thin slices fresh galangal (about 1 inch total), or 1 tablespoon galangal paste
Galangal is sharper and more piney than ginger. Fresh ginger is the closest common substitute, though the flavor will be slightly warmer and less citrusy.
6 fresh or frozen makrut lime leaves, torn
Tear them to release the oils and leave them whole in the pot. If you cannot find them, use the zest of 1 lime plus 1 teaspoon lime juice at the end.
2 (13.5-ounce / 400ml) cans full-fat coconut milk
Full-fat is essential for the creamy body; light coconut milk turns the soup thin. Shake the cans well before opening, or whisk in a bowl if the cream has separated.
4 cups (960ml) low-sodium chicken broth
Use homemade or a good-quality carton broth; vegetable broth makes it vegetarian if you swap the fish sauce for soy sauce.
2 tablespoons fish sauce, plus more to taste
Three Crabs or Red Boat brand gives the cleanest flavor. Soy sauce or coconut aminos is the vegetarian swap, though you will need a pinch more salt.
1 tablespoon palm sugar (or light brown sugar)
Palm sugar has a rounded caramel note; light brown sugar is a fine substitute and honey works in a pinch.
3 tablespoons fresh lime juice (about 2 limes), plus wedges for serving
Add it off the heat so the brightness survives. Bottled lime juice is acceptable but noticeably flatter.
1/4 cup chopped fresh cilantro, plus sliced Thai chilies and lime wedges for serving
Thai basil or scallions can stand in for cilantro; add the chilies at the table so heat stays adjustable.
Tips & Tricks
Do not boil the coconut milk
keep the slow cooker on Low and add the coconut milk in the last 30 minutes if your model runs hot, or the fat can split and turn grainy.
Leave the aromatics whole
lemongrass, galangal, and lime leaves are meant to flavor the broth and be fished out or pushed aside, not eaten.
Season at the end
fish sauce and lime juice added after the heat is off taste brighter and let you adjust salt and sourness to your liking.
Use thighs, not breast, for a long cook
thighs stay juicy after hours of simmering, while breast turns stringy.
Pro Tips
Step-by-Step Instructions
1. Layer the aromatics
Add the onion, lemongrass, galangal, and torn lime leaves to the bottom of a 6-quart slow cooker. This is the flavor base that will perfume the whole pot.
2. Add chicken and broth
Scatter the chicken thighs and mushrooms over the aromatics, then pour in the chicken broth. Do not add the coconut milk or lime juice yet.
3. Slow cook on low
Cover and cook on Low for 5 to 6 hours (or High for 2 1/2 to 3 hours) until the chicken shreds easily with a fork and reaches 165°F (74°C) on an instant-read thermometer. The broth should smell strongly of lemongrass.
4. Stir in coconut milk
Stir in the coconut milk, palm sugar, and fish sauce, cover, and cook on Low for 15 more minutes until steaming but not bubbling hard, about 190°F (88°C).
5. Fish out aromatics
Use tongs to remove the lemongrass stalks, galangal slices, and lime leaves, pressing them against the side of the pot to release any broth. Leaving them in makes the soup bitter and unpleasant to eat.
6. Finish with lime
Turn off the slow cooker and stir in the lime juice and cilantro. Taste and add more fish sauce for salt or lime for brightness, one teaspoon at a time, until the broth tastes balanced.
7. Serve hot
Ladle into bowls and top with extra cilantro, sliced Thai chilies, and lime wedges. Serve with jasmine rice on the side to soak up the broth.
Delicious Variations
Shrimp tom kha
swap the chicken for 1 pound of raw shrimp added in the last 10 minutes of cooking, just until pink and curled.
Vegetarian tom kha
use vegetable broth, soy sauce instead of fish sauce, and add cubed extra-firm tofu with the mushrooms.
Extra-vegetable version
add 1 cup of sliced red bell pepper and 1 cup of halved cherry tomatoes in the last 45 minutes for color and sweetness.
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 flavors deepen overnight.
Freezer
Freeze in portions for up to 2 months, but expect the coconut milk to separate slightly; whisk vigorously after reheating.
Reheating
Reheat gently on the stovetop over medium-low heat, about 3 to 4 minutes, stirring often; do not boil or the coconut milk may split.
Frequently Asked Questions
Q: Can I use chicken breast instead of thighs in tom kha soup?
Yes, but add it later so it does not dry out. Cut two large breasts into 1-inch pieces and stir them in during the last 90 minutes on Low, cooking until they reach 165°F (74°C).
Q: What can I use instead of galangal and lemongrass?
Fresh ginger is the best substitute for galangal, and lemongrass paste or lime zest stands in for fresh lemongrass. The flavor will be slightly different but still fragrant and delicious.
Q: How do I keep coconut milk from curdling in the slow cooker?
Keep the heat on Low and stir the coconut milk in near the end rather than at the start. High heat and long boiling are what cause the fat to split and turn grainy.
Q: Is tom kha soup spicy?
Traditional tom kha is mildly spicy at most, with the heat coming from chilies added at the table. The broth itself is creamy, sour, and aromatic rather than hot, so it is family-friendly.
Q: Can I make this tom kha soup ahead of time?
Yes, it tastes even better made a day ahead and reheated gently. Cook it fully, cool it quickly, refrigerate up to 4 days, and add a squeeze of fresh lime when reheating.
Make this slow cooker tom kha soup this week and let the pot do the work while you get on with your day. If you try it, leave a comment with the swaps you used and snap a photo of your steaming bowl.
Slow Cooker Tom Kha Soup (Thai Coconut Chicken Soup)
This slow cooker tom kha soup is creamy Thai coconut chicken soup made hands-off, with tender chicken, mushrooms, and bright lemongrass broth.
🧂 Ingredients
- 1 1/2 pounds (680g) boneless, skinless chicken thighs, cut into 1-inch pieces
- 8 ounces (225g) cremini mushrooms, sliced 1/4 inch thick
- 1 medium yellow onion, thinly sliced
- 3 stalks fresh lemongrass, tough outer layers removed, cut into 2-inch lengths and bruised
- 5 thin slices fresh galangal (about 1 inch total), or 1 tablespoon galangal paste
- 6 fresh or frozen makrut lime leaves, torn
- 2 (13.5-ounce / 400ml) cans full-fat coconut milk
- 4 cups (960ml) low-sodium chicken broth
- 2 tablespoons fish sauce, plus more to taste
- 1 tablespoon palm sugar (or light brown sugar)
- 3 tablespoons fresh lime juice (about 2 limes), plus wedges for serving
- 1/4 cup chopped fresh cilantro, plus sliced Thai chilies and lime wedges for serving
📋 Instructions
- 1Layer the aromatics — Add the onion, lemongrass, galangal, and torn lime leaves to the bottom of a 6-quart slow cooker. This is the flavor base that will perfume the whole pot.
- 2Add chicken and broth — Scatter the chicken thighs and mushrooms over the aromatics, then pour in the chicken broth. Do not add the coconut milk or lime juice yet.
- 3Slow cook on low — Cover and cook on Low for 5 to 6 hours (or High for 2 1/2 to 3 hours) until the chicken shreds easily with a fork and reaches 165°F (74°C) on an instant-read thermometer. The broth should smell strongly of lemongrass.
- 4Stir in coconut milk — Stir in the coconut milk, palm sugar, and fish sauce, cover, and cook on Low for 15 more minutes until steaming but not bubbling hard, about 190°F (88°C).
- 5Fish out aromatics — Use tongs to remove the lemongrass stalks, galangal slices, and lime leaves, pressing them against the side of the pot to release any broth. Leaving them in makes the soup bitter and unpleasant to eat.
- 6Finish with lime — Turn off the slow cooker and stir in the lime juice and cilantro. Taste and add more fish sauce for salt or lime for brightness, one teaspoon at a time, until the broth tastes balanced.
- 7Serve hot — Ladle into bowls and top with extra cilantro, sliced Thai chilies, and lime wedges. Serve with jasmine rice on the side to soak up the broth.
