Gluten-Free Tom Kha Gai (Thai Coconut Chicken Soup)

Why You’ll Love This Recipe

• Classic Tom Kha Gai flavors: lemongrass, galangal, and lime in a silky coconut broth.
• Naturally gluten-free with gluten-free fish sauce and stock—no soy sauce needed.
• Weeknight-friendly: simple steps, just 45 minutes start to finish.
• Easy to customize heat and protein while keeping the soup balanced and bright.

Grocery List

• Produce: Lemongrass, galangal (or ginger), makrut lime leaves, Thai chiles (or serrano), mushrooms, limes, cilantro, scallions.
• Dairy: None.
• Pantry: Unsweetened coconut milk (1 full-fat, 1 light), gluten-free chicken stock, gluten-free fish sauce, palm sugar (or light brown sugar), kosher or sea salt.

Full Ingredients

Aromatic Broth

• 3 cups (720 ml) gluten-free low-sodium chicken stock
• 2 stalks lemongrass, tough outer leaves removed, trimmed to 6-inch (15 cm) pieces and bruised
• 10 thin slices fresh galangal (about 1/8-inch/3 mm each) or 8 slices fresh ginger
• 6 makrut (kaffir) lime leaves, torn to release oils
• 2–3 Thai bird’s eye chiles, slit lengthwise (seeded for less heat)

Soup and Protein

• 1 lb (450 g) boneless skinless chicken thighs or breast, very thinly sliced crosswise
• 8 oz (225 g) mushrooms (oyster, straw, or cremini), sliced 1/4-inch (6 mm)
• 1 (13.5 oz/400 ml) can unsweetened full-fat coconut milk
• 1 (13.5 oz/400 ml) can unsweetened light coconut milk

Seasoning and Finish

• 3 tbsp gluten-free fish sauce (check label)
• 2 tsp palm sugar or light brown sugar
• 3 tbsp fresh lime juice (from about 2 limes), plus lime wedges for serving
• 1/2 cup loosely packed cilantro leaves and tender stems, roughly chopped
• 2 scallions, thinly sliced
• Sea salt, only if needed (the fish sauce is salty)
• Extra thinly sliced Thai chiles, for garnish (optional)

Step-by-Step Instructions

Step 1: Prep the aromatics and produce

Trim and bruise the lemongrass by lightly smashing the stalks with the back of a knife to release oils. Slice the galangal (or ginger) thinly. Tear the makrut lime leaves. Slit the chiles lengthwise. Slice the mushrooms and thinly slice the chicken across the grain so it cooks quickly and stays tender.

Step 2: Build the aromatic broth

In a medium pot, combine the gluten-free chicken stock, lemongrass, galangal, lime leaves, and chiles. Bring just to a gentle simmer over medium heat, then reduce to maintain 180–185°F (82–85°C). Simmer, uncovered, for 10 minutes to infuse the stock without boiling.

Step 3: Poach the mushrooms and chicken

Add the mushrooms and the sliced chicken to the pot. Keep the heat gentle (no rolling boil) and cook for 6–8 minutes, stirring occasionally, until the chicken is opaque and cooked through, reaching 165°F (74°C) at the center of the thickest piece.

Step 4: Enrich with coconut milk and season

Pour in both cans of coconut milk. Add the gluten-free fish sauce and palm sugar. Warm the soup for 3–4 minutes, keeping it below a simmer at 175–185°F (80–85°C) to prevent the coconut milk from separating.

Step 5: Brighten with lime

Remove the pot from heat. Stir in the lime juice. Taste and adjust: add more fish sauce for saltiness, a pinch more sugar to round the acidity, or an extra squeeze of lime for brightness. If desired, fish out the lemongrass stalks, galangal slices, and lime leaves before serving.

Step 6: Finish with fresh herbs

Stir in the cilantro and scallions. Let the soup rest for 1–2 minutes so the herbs perfume the broth without wilting completely.

Step 7: Serve

Ladle into warm bowls. Garnish with extra chile slices and more cilantro if you like. Serve immediately with lime wedges on the side. If pairing with rice, choose plain jasmine rice (naturally gluten-free) and keep it on the side so the soup’s delicate balance stays vivid.

Pro Tips

• Keep it gentle: maintaining 175–185°F (80–85°C) prevents the coconut milk from splitting and keeps the broth silky.
• Slice chicken thinly across the grain for tender bites that cook in minutes.
• If substituting ginger for galangal, add 1 extra makrut leaf (or a strip of lime zest) to boost citrusy aroma.
• Season at the end: fish sauce, sugar, and lime should be balanced to your taste—salty, sweet, and sour in harmony.
• Use clearly labeled gluten-free fish sauce and gluten-free stock to avoid hidden gluten.

Variations

• Shrimp Tom Kha: Swap in 1 lb (450 g) large shrimp, peeled and deveined. Add with the mushrooms and cook 2–3 minutes until pink and just opaque.
• Vegetarian/GF: Use gluten-free vegetable stock and a gluten-free vegan “fish sauce” or coconut aminos plus sea salt. Replace chicken with 14 oz (400 g) firm tofu, cubed, and double the mushrooms.
• Extra-herb: Add a small handful of Thai basil or cilantro right before serving for a vibrant, anise-kissed finish.

Storage & Make-Ahead

Refrigerate leftovers in an airtight container for up to 3 days. Reheat gently on the stove over low heat to 160–170°F (71–77°C); do not boil. For best flavor, add fresh lime juice and herbs just before serving if you plan to make the soup ahead. Coconut-based soups do not freeze well (the texture can split), so freezing is not recommended.

Nutrition (per serving)

Approximate values: 410 calories; 25 g fat; 6 g carbohydrates; 23 g protein; 1,150 mg sodium. Values will vary based on exact brands and cuts of chicken.