Thai BBQ Chicken (Gai Yang)

Andy | Dinner | Thai

Prep time: 2 min Cook time: 15 min Servings: 4

Gai Yang is BBQ chicken from northeastern Thailand, rooted in the food traditions of the Isaan region and influenced by Lao cooking.

This dish is all about the marinade which has lemongrass, coriander roots, garlic, palm sugar, fish sauce and dark soy sauce blended into a fragrant paste that coats the chicken and chars on the grill. The palm sugar caramelises under high heat, which is where that deep colour and slightly smoky-sweet crust comes from. It’s a simple technique, but you'll end up with some very tasty chicken. I’ve used boneless thighs here because they cook evenly, stay juicy under direct heat and hold up to the acid in the marinade without going stringy.

The Nam Jim Gai is the other half of the dish: a sweet, sour and gently spiced dipping sauce made with rice vinegar, fresh chilli and garlic, thickened with tapioca starch to a glossy consistency. Make the sauce while the chicken marinates and it’ll be cooled and ready by the time you fire up the grill. Serve with steamed jasmine rice and sliced cucumber.

Ingredient Notes

Palm sugar: A dense, amber-coloured sugar made from the sap of the palmyra palm, with a mild caramel depth that refined white sugar doesn’t have. It comes in solid discs or blocks, so chop or grate it before it goes into the processor. It also caramelises more readily than white sugar, which contributes to the char on the grill. If you can’t find it at an Asian grocer, caster sugar or brown sugar are the closest substitutes. Brown sugar will add a slight molasses note, but it works well.

Lemongrass: Only the lower pale section of the stalk is used: the upper green leaves are fibrous and add very little flavour. Peel away the outer layer to expose the more tender core, then chop as finely as you can before it goes in the processor. The finer you chop it beforehand, the smoother the marinade paste will be. Lemongrass keeps well in the fridge for a few weeks and also freezes without any loss of flavour.

Coriander roots: The roots carry a much more concentrated, earthier flavour than the leaves, and they hold up better under heat and acidity, which makes them ideal for marinades. Most supermarket bunches still have the roots attached: trim them off, rinse away any soil and add them straight to the processor. If your bunch has been trimmed at the base, the lower stems are a reasonable substitute, though the flavour will be a little lighter.

Equipment

Chopping board
Chef’s knife
Small food processor or mortar and pestle
Large bowl
BBQ grill or grill pan
Medium saucepan
Small bowl
Tongs
Meat thermometer

Ingredients

1 shallot
1 lemongrass
4 cloves garlic
small handful coriander roots
1 tsp palm sugar
Juice of 1 lime
1 tbsp neutral flavoured oil (like peanut)
1 tbsp Thai dark soy sauce
1 tsp rice vinegar
1 tbsp fish sauce
ground white pepper, to season
8 chicken thighs, boneless, skinless
steamed rice, sliced cucumber, to serve
Nam Jim Gai
4 cloves garlic
3 to 4 red Thai chilies
120g caster sugar
120ml rice vinegar
120ml water, + 20ml extra for slurry
1 tbsp fish sauce
1 tsp tapioca starch
salt, to season

Directions

Prep the marinade
Roughly chop the shallot and finely chop the lemongrass stem. Place in a small food processor with the garlic, coriander roots, palm sugar, lime juice, oil, soy sauce, rice vinegar and fish sauce. Season with some white pepper and process until a rough paste.
Transfer to a large bowl and add the chicken thighs. Mix well until the chicken is completely coated. Cover and refrigerate for 2 hours to marinate, up to overnight.
Make Nam Jim Gai
Place the water, rice vinegar, sugar and fish sauce in a medium saucepan. Season with salt and place over a medium heat.
Bring to a gentle simmer, stirring until sugar dissolves.
Roughly chop the garlic and chillies and process in a small food processor until finely minced. Transfer to the saucepan and mix through. Simmer for 2-3 minutes.
Mix the tapioca starch with the extra water in a small bowl to a slurry, then add to the saucepan. Bring to a boil, stirring continuously, and cook for 1 minute until thickened slightly and glossy.
Remove from the heat and allow to cool completely.
Grill chicken and serve
Preheat a lightly oiled BBQ grill or grill pan over medium-high heat.
Remove the chicken from the marinade and grill, turning to char well on both sides, about 6-8 minutes, until the internal temperature reaches 65°C.
Remove from the grill and set aside to rest for 5 minutes. It will come up to 70°C-72°C in temperature while it rests.
Serve the chicken with some steamed rice, sliced cucumber and Nam Jim Gai.

Recipe notes

Chef Tips

Marinate for at least 2 hours, no more than 24

The lime juice and rice vinegar in the marinade will start to break down the proteins in the chicken if left too long. Two hours gives solid flavour penetration; overnight in the fridge is the sweet spot for meal prep. Beyond 24 hours the texture can turn slightly mushy: still safe to eat, but the quality drops noticeably. Set a reminder if you’re marinating overnight so it doesn’t run long.

Pull the chicken at 65°C and rest

Boneless thighs cook quickly at medium-high heat and can go from underdone to overdone faster than you’d expect. I pull them off the grill at 65°C and rest for 5 minutes: carryover cooking will bring the internal temperature up to around 70°C-72°C, which is where you want to be. A meat thermometer takes the guesswork out of it, especially on a BBQ where the heat is less controlled. Thicker pieces may need an extra minute or two.

Storage

Leftover chicken keeps in an airtight container in the fridge for up to 3 days. Reheat in a hot grill pan or under a grill rather than the microwave: the direct heat brings back some of the char and keeps the texture. The Nam Jim Gai will keep in a sealed jar in the fridge for up to a week. It thickens as it cools but returns to the right consistency at room temperature or with a brief warming over low heat.

FAQs

Can I use bone-in chicken? Yes, and it works well. Bone-in thighs or a butterflied whole chicken will take significantly longer on the grill: allow 12-15 minutes for bone-in thighs and 30-40 minutes for a whole butterflied bird depending on size. Always check the internal temperature near the bone to confirm it’s cooked through.

Can I make this ahead? Yes. The chicken can be marinated up to 24 hours in advance and kept covered in the fridge. The Nam Jim Gai can be made 2-3 days ahead and stored in a sealed container. At serving time you just need to grill the chicken, which takes less than 10 minutes.

Can I cook it inside? Yes. A heavy grill pan or cast iron skillet over high heat works well and you’ll still get a decent char. Cook in batches and avoid crowding the pan: too many pieces at once will drop the temperature and steam the chicken rather than grill it. Open a window or run the extractor fan: the marinade will smoke.