Gaeng Khiao Waan Gai (Thai Green Curry with Chicken)

Gaeng khiao waan gai, or green curry with chicken, is one of the most well-known and popular Thai curries in the world. A rich coconut milk-based curry, part of its crowd-pleasing nature is its balance: it’s spicy, but not too spicy; it’s sweet, but not too sweet; and the richness of the coconut milk pairs well with the relative leanness of chicken meat. The curry takes its name from the green chiles used to make prik gaeng khiao waan, the curry paste that forms its base, which also contains fresh aromatics, like lemongrass, galangal, garlic, and shallots, along with dried spices and shrimp paste. (The curry paste is fundamentally identical to the red curry paste, prik gaeng phet, used to make red curry, or gaeng phet, aside from the fact that it uses green chiles instead of dried red chiles.)

Like many Thai dishes, there’s a lot of speculation about its origins. Hanuman Aspler, a scholar of Thai food and one of my mentors, has noted that green curry is a relatively new addition to Thai cuisine, one that likely originated in the kitchens of the Thai aristocracy sometime during the 1920s. In his examination of historic Thai cookbooks, Aspler found few if any mentions of green curry, just red curry. And although there’s no definite answer as to why green chiles came to be used in place of red chiles to make green curry paste, there is speculation that the substitution came about due to the influence of Indian-style curries.

However, there's a lot of debate in both historical and current cookbooks, as well as in many articles, about how green curry should be seasoned. Many people look at the curry’s name and believe the curry should be quite sweet, which they accomplish by adding a lot of sugar, and quite green, which they accomplish by blending things like cilantro leaves and spinach leaves into the curry paste, as “khiao” means green and “waan” means sweet. But, as Hanuman explains, “khiao waan” is based instead on the words “aawn waan,” which means a pastel green color—it has nothing to do with sweetness—and since this curry is essentially a gaeng phet (red curry), its flavor profile should follow suit: it should be assertively savory and spicy thanks to the curry paste and a generous splash of fish sauce, with just a hint of background sweetness coming from palm sugar and coconut milk.

The dish itself comes together very quickly—provided you’ve made the prik gaeng khiao waan ahead of time, or you’re using a store-bought  curry paste—and follows the standard cooking procedure for most coconut milk-based curries. Curry paste and coconut milk are cooked down until the water content of both has evaporated, causing the coconut milk emulsion to break or “crack,” with fat separating from the solids. At this point the paste begins to fry in the coconut oil, intensifying the fat-soluble volatile aromas of the chiles, dried spices, and fresh aromatics. This process deepens the flavors of the curry paste and carries them through into the finished dish.

After seasoning with fish sauce and palm sugar, chicken thigh pieces and floral makrut lime leaves are added, along with more coconut milk that has been thinned out with water, and the curry is brought to a simmer. This thinned coconut milk mixture mimics the texture of hang gati, the “tail,” or second or third pressing of coconut milk, which is much lighter and subtly flavored compared to the rich and thick hua gati, or “head” of coconut milk (also sometimes referred to as coconut cream) that’s “cracked” or broken in the first frying step of the curry’s preparation. Once the chicken is just cooked through, small Thai apple eggplants are added to the mix. The eggplants are crisp and slightly bitter, and along with the tender chicken, they provide textural contrast and a little respite from the heat and punch of the saucy curry. A handful of sweet (a.k.a. Thai) basil leaves are stirred in at the last minute, and the dish is garnished with finely sliced makrut lime leaves.

This is a thick, rich, green curry that can be served as part of a larger meal, and it pairs especially well with cooked jasmine rice, a fried fish or omelette, a sour and spicy soup like tom yam, or a simple stir-fry like galam plee pad nam pla (stir-fried cabbage with fish sauce and garlic).