After my recipe for Tom Yam soup, I got many emails asking me for a Tom Kha soup recipe too. It’s another crowd pleaser, and in contrast to Tom Yam, is milder, creamier, and richer. In Tom Yam, the citrus flavours of lemongrass and lime leaves take the lead, but Tom Kha’s earthy flavour comes from Kha or galangal as you might know it.
What follows is the recipe I used to make Tom Kha Gai at my former restaurant. This is by no means the one true method. As with almost any well-known dish on this planet, you can make changes to suit your taste and style. I will suggest some of them in the “notes” section after the recipe. Give each a try, and you might find a new personal favourite.
Makes 2-3 bowls of soup
Preparation time: 15-20 minutes
WHAT YOU NEED
Good quality Chinese chicken stock – 1 cup
Coconut milk – 1 cup
Fresh or frozen lemongrass – 1/2 a stalk
Galangal – fresh – 6 slices
Kaffir Lime Leaves – 2 (hand-torn)
Thai bird’s eye chillies (or Serrano chillies) – 2-3 (big slices so you can avoid them easily)
(If you don’t have any of the above, Amazon ships a package of all the fresh ingredients you need for the soup.)
Fish sauce – 1 tbsp (The saltiness can vary a lot across brands, so start with less always.)
Lime juice – 2 tbsp
Sugar – 1/2 tsp
Coriander (cilantro for the Americans) leaves – 2 tbsp
Boneless chicken breast – 50 gm (chopped)
Straw mushrooms (or regular button mushrooms) – 4 (sliced)
HOW TO MAKE IT
For the lemongrass, use only the bottom white part (about 6 inches) and discard the woody grass part of it. With the flat side of a cleaver or a heavy object, pound and bruise the lemongrass so it releases the flavour. Cut into 2 inch segments. (Watch yourself with the cleaver, please. We only want to bruise the lemongrass, not your fingers.)
Put the stock into a pot and bring to a boil. Toss the galangal, lemongrass, sugar, and lime leaves in. Simmer for 5 minutes.
Add the coconut milk, chillies, fish sauce and simmer for another 5 minutes.
Finally, add the chicken and mushrooms and cook till the chicken is just cooked. The moment you see it turning all white on the outside, it’s 90% done.
Turn off the heat, add lime juice and garnish with coriander leaves. Test for saltiness and sourness. You should get the earthy flavour of galangal, noticeable amount of saltiness, sweetness from the coconut milk, and a fair bit of lime flavour, with a hint of chilli in the background. If required, adjust with more fish sauce (salt) and lemon juice (sour).
(Why do I add the lime juice at the end instead of adding it with everything else, you ask? Because the flavour of the lime gets mellowed when it’s cooked. You need it fresh and bursting on your tongue.)
Pretty simple, ain’t it?
1) This tastes great with prawns (shrimp) or mixed seafood instead of chicken. To turn this into Tom Kha Goong (Prawns), use prawns instead of chicken but add it only in the final 1 minute of cooking. Prawns cook very fast and will continue to cook in the warm stock. Overcooking them will turn them tough and leathery. Frozen prawns (nude) suck. Don’t use them.
For a mixed seafood soup, add some fish chunks (use a mild-tasting fish) and some squid (calamari.) Add the fish to the soup a couple of minutes before the prawns, and add the squid at the same time as the prawns.
Oh, and I have not forgotten you vegetarian people either. :) You can make a Tom Kha Hed with mushrooms instead of chicken. Add a variety of mushrooms if you can (I love Shitake mushrooms). Don’t like mushrooms? Use other veggies. Use vegetable stock instead of chicken stock. Use 1/2 tsp salt instead of the fish sauce. Add a couple of pieces of tofu if you like. There, you’re done, amigo!
2) Galangal has no real substitute. Ginger does a poor job. In this soup especially, the whole point is the galangal flavour, so ginger simply won’t do. (Tom Kha means “boiled galangal”.)
3) This recipe makes a soup that’s not as rich as you might have had at other restaurants. This is simply my personal preference because most of my customers order it as a soup course instead of something to eat with rice as Thai people have it. So I didn’t want to weigh their tummies down. If that’s the kind of soup you prefer, however, you can replace the coconut milk in this recipe with half coconut milk and half coconut cream. Reserve a tablespoon of coconut cream to stir into the soup at the end of cooking. If you’re not a fan of the lime flavour, reduce the amount of lime juice too.
4) If you’ve seen this soup with a reddish hue, it’s probably because some Nam Prik Pao (roasted chilli paste) was added instead of the regular fresh chillies. I’m not a fan of doing that, but it’s up to you. I’ve also seen versions that use dried red chilli flakes to add flavour.
5) Good chicken stock is very simple to make. Take 1 kg chicken wings, throw in a couple of drumsticks for meat, put it in a tall stock pot, cover with 2 litres cold water, and bring to a simmer. When the scum rises to the top, skim to another bowl with a shallow spoon. This should take 10-20 minutes. When the stock is clear, toss in 4 spring onions (scallions; use only the white part), 5-6 slices of ginger, and a teaspoon of black peppercorns. Let this simmer for 2-3 hours (it should only bubble). Two rules for good stock: a) do not stir and b) do not boil (or it will become cloudy instead of clear.)
After the stock has finished simmering, let it stand for 20 minutes and then using a fine mesh sieve, strain it into another bowl. Using a muslin cloth would be a good idea. Your stock is ready. If you leave it in the fridge, the fat will solidify on the top. Just remove this fat and you have de-fatted, unsalted stock ready for use. You can even reduce the liquid and make stock cubes in the freezer.
6) The strength of lemongrass and lime juice may vary in your part of the world, so use your nose and your tongue to judge proper quantities. When in doubt, use more lemongrass but less lime juice. Then adjust gradually. :)
In temperate climates, you may not get limes. If so, use lemon juice instead, and use more of it than prescribed here.