Tom Kha Gai: Thai Chicken Soup

Tom Kha Gai, Thai for boiled galangal and chicken, is a deliciously complex and structured soup. Perhaps surprising, but the galangal, coconut milk, chili peppers, lemongrass, and kaffir limes yield an impressive balance of spicy, creamy, sweet, and sour flavors—all with an enticing aroma.

This quintessential Thai soup calls for a lot of uncommon-in-the-west ingredients, but with luck you can find them in higher-end or larger supermarkets, and certainly in any Asian specialty store. On the bright side, once you assemble the inputs, both preparation and cooking are short and simple.

Tom Kha Gai

This is an authentic approach, but it is my approach—I am faithful to the traditional recipe, but the proportions are born of my own experimentation and I have made small modifications, such as the omission of the straw mushrooms and the use of chicken thighs in lieu of breast.

Makes 4 soup course-sized servings or 2-3 large.

Ingredients:

2 cups chicken stock
8 slices fresh baby galangal (kha)
2 stalks lemongrass (takhrai), only the lower white portion, bruised, 2" slices
4 fresh kaffir lime leaves (bai makrut), hand-torn in half
1 tablespoon palm sugar (nam taan pep), granulated
2 14oz (400ml) cans coconut milk
1 tablespoon fish sauce (nam pla)
8 red thai bird's eye chili peppers (prik ki nu), sliced
2 teaspoons Thai roasted red chili paste (nam prik pao), store bought or homemade (recipe)
2 limes, kaffir if possible, juiced and zested
1 lb boneless and skinless chicken thighs (gai), trimmed of fat and sliced into large strips
2 shallots, 1/4" dice
1 large red bell pepper, sliced
gray salt, to taste
red pepper flakes, to garnish
1 bunch fresh cilantro, roughly-chopped, to garnish

Add the chicken stock, baby galangal, lemongrass, kaffir lime leaves, and palm sugar to a large stock pot. Bring to a boil. Lower heat to a simmer and let cook, stirring occasionally, for four minutes.

Simmering

Add the coconut milk, fish sauce, roasted red chili paste, Thai chili peppers, and lime zest. Continue simmering, stirring occasionally, for four more minutes.

Add the chicken, shallot, and red bell pepper. Raise heat to high. Once just starting to boil, lower heat and simmer until the chicken is cooked, only 4-5 minutes.

Chicken added and cooking

Add the lime juice, stirring. Taste and adjust salt. Depending on the saltiness of your fish sauce and stock, you likely need little salt.

Serve, garnished with red pepper flakes and a lot of chopped cilantro. Pairs well with a spicy Alsatian Gewürztraminer or a Thai pale lager such as Singha.

Tom Kha Gai, plated and ready to serve

On color: To produce a whiter (less yellow) soup, as traditionally served, use light (unroasted) chicken stock. Additionally, omitting the roasted red chili paste, or adding it at the end and not fully incorporating, yields a whiter soup.

On alternative ingredients: Unfortunately, there are not great substitutes for this soup's various Thai inputs. If you cannot find fish sauce, then just skip it and add extra gray salt. Turbinado (raw) sugar is an acceptable substitute for palm sugar. If you do not have kaffir lime leaves, add more zest or juice from limes you do have. No lemongrass? Skip it. In a pinch, as shown in these photos, Serrano peppers stand in for Thai. Galangal is the most missed. Despite the sobriquet blue ginger, galangal tastes only passingly like ginger. Unfortunately for those who cannot find galangal—and many highend markets, and all Asian markets, carry it—this soup is all about the rhizome. If you must, by all means cook without it, but understand that the result is a different (yet still delicious) beast.

Variation: It would not be my choice, but you can substitute the chicken for prawns and create Tom Kha Goong. The prawns will cook much faster than the chicken, requiring only 60-90 seconds.