Tom Kha Gai (Thai Galangal and Chicken Soup) with Oyster Mushrooms

tomkhagai_Galangal, lemongrass, makrut lime leaves, coriander root, chilli, lime juice… In this famous soup Thai flagship ingredients’s flavours are perfectly recognisable, one by one, creating a recurrent mixture of sour, salty and hot flavours, embellished with a typical sharp aroma. This dish perfectly illustrates the elegance and sophistication of Thai cuisine one might not necessarily see throughout years of eating sloppily prepared curries, served in so many restaurants in Europe (and maybe elsewhere too).

“Tom kha gai” means roughly a dish with galangal (tom kha) and chicken (gai) and this soup does contain a particularly high dose of galangal root, which slightly dominates it. I have followed here the recipe from David Thompson’s Thai Food (a most extraordinary cookery book I recommend to every Thai food lover) and as the author suggested, apart from the chicken, I added also some delicate-tasting mushrooms (oyster mushrooms proved perfect). (In the meantime I made a test with cultivated button mushrooms (aka “cremini”, when they are brown) and their taste was too strong).

I tried to make this dish as close to the original as possible, but I won’t pretend it is (mainly due to what I did with coconut milk and cream). I have cut down the coconut milk amounts and skipped the coconut cream, replacing both liquids with more chicken stock. The original version was just too fatty and rich for me. (In fact I do this very often in Thaï dishes, just like I cut down on cream and fat in Western cuisine). I have also added more chicken meat and more mushrooms in order to make it a very filling one-course meal, easily served with rice or bread; not to mention the amounts adapted to a dish for two. I encourage you to check the extraordinary David Thompson’s Thai Food for the original recipe.

TIPS: This dish is a good way to test if you are able to cook certain genuine Thai dishes… because its ingredients appear in almost every curry (and I assume curries are what most Thai food lovers try to make at home first). In short, if you can find fresh (or at worst frozen) lemongrass, makrut lime leaves, galangal root and coriander roots, then you are almost ready to buy David Thompson’s book without being utterly frustrated (there are some other products, such as fresh peppercorns, Thai basil, holy basil, grachai, makrut lime zest… but these aren’t used as often as former ingredients). From my experience, the smallest damage through freezing is done to makrut lime leaves and coriander roots. Lemongrass and galangal become mushy and the galangal’s taste changes, but it’s still better than using dried versions.

Coriander roots are particularly difficult to get for some people, but I have recently read on a forum a fantastic trick: buying a potted plant in a gardening shop! Of course, if you are able to grow your own herbs on a balcony, windowsill or in a garden, finding roots should no longer be a problem. You can also ask a farmers’ market vendor to bring you next time coriander with roots or only roots (I’m sure many would happily give them for free).

If you use frozen makrut lime leaves (I can find them here only frozen), double the amount because they are less aromatic (in general, if using frozen vegetables in Thai dishes, I increase their amounts).

Preparation: about 30 minutes

Ingredients (serves two):

400 ml chicken stock

250 ml coconut milk

1 big chicken breast (skinned)

250 g oyster mushrooms, tough stalks removed (or other delicately flavoured mushrooms)

7 thin slices of fresh galangal

pinch of salt

1/2 flat teaspoon palm sugar

1 big thick stalk lemongrass or two thin stalks (whole, only the tough end trimmed)

2 small Asian red shallots (I have used 1 medium European shallot)

1 big coriander root

2 red bird’s-eye-chillies + 2-3 more for the final serving stage

2 makrut (also known as kafir) lime leaves (if you have frozen lime leaves, see the TIPS)

2 tablespoons fish sauce (or more)

1 tablespoon lime juice (or more)

coriander leaves

Pour the stock and the coconut cream into a pan.

Bring to the boil.

In the meantime wash the mushrooms and tear them into bite-sized pieces.

Slice very finely the chicken breast and sprinkle with salt (do not add too much salt).

Put aside.

Place the shallots, the lemongrass stalk, the coriander root and the bird’s-eye-chillies in a mortar and bruise them with a pestle. You can also do it, placing them on a cutting board and using an ice “pestle” for cocktails (this is what I did) or any other heavy object.

Put aside 2-3 chillies for the final serving stage.

Place the remaining bruised vegetables into the boiling stock, adding salt, palm sugar, galangal and lime leaves.

Let it simmer for about ten minutes.

Add the mushrooms and after 5 minutes, the finely sliced chicken breast.

Continue simmering until the mushrooms and the chicken are done.

Mix the lime juice, the fish sauce, the additional bird’s-eye-chillies and the coriander leaves in an empty serving bowl. Pour the soup over it, stir well, adjust the taste – the author says it should taste rich, salty, sour and hot, though if you have “thinned” the stock, as I did it won’t taste very rich – and serve.

I prefer dividing the sauce, the juice, etc. into individual bowls and then putting the fish sauce and a piece of lime on the table, so that I can still adjust the taste.

19 Replies to “Tom Kha Gai (Thai Galangal and Chicken Soup) with Oyster Mushrooms”

  1. I didn’t know the ‘kha’ part of the name referred to galangal. You learn something new every day. 🙂

    The soup looks delicious though I’d have to substitute for the coriander root, galangal and lime leaves in the recipe. Everything else is easily available. Probably the galangal and lime leaves is available too but I’d have to make a special trip to the International grocery store and I usually go crazy in there and spend WAY too much money.

    1. Thank you, A_Boleyn. I don’t want to sound harsh, but a galangal soup without galangal would be like a tomato soup without tomatoes 🙂 Seriously, I cannot think of anything to substitute kaffir lime leaves or galangal. Nothing is similar. As for the coriander roots, some people substitute with coriander stalks (lower part) but the taste and aroma is much much stronger (here it might work since coriander leaves are present too). This soup is so simple, has few ingredients and flavours are so distinct, I think kaffir lime leaves and galangal are as crucial as the lemongrass. Other Thai recipes might be maybe more forgiving… but I would never make this one without a trip to my Vietnamese/Thai shop.

  2. I love the combination of coconut milk, and lemon grass. Aside from the beautiful aroma, It has that rich-sourly flavor that I like on Thai dishes. Thank you for posting this recipe, Sissi. I hope you are having a lovely week! 🙂

    1. Thank you so much, Ray. I totally agree! Sadly this sour and hot flavour is often seriously toned down in restaurants here… I discovered it only thanks to this wonderful book.

  3. I have ordered this soup in Thai restaurants many times because it’s a dish I figured that I would never be able to duplicate at home. Looking at your list of ingredients, that may still be the case. I have never heard of using coriander root in a dish before. VERY interesting! I do try to grow coriander every year, unsuccessfully, so maybe I should start saving the roots. 🙂 Now for the lemongrass and kifer leaves – I have bought in powdered form in the pantry. Would the powdered form work? The flavors of this soup are amazing and I would love to be able to make it at home. Thanks!

    1. Thank you so much, MJ. I agree about the amazing flavours! As you see there are very few ingredients and the soup is very quick to make, but, yes… these ingredients. The problem of Thai cuisine is that it requires fresh ingredients. (Japanese or Korean cuisine is so much easier to cook!). As I told A_Boleyn, at worst coriander root might be substituted with coriander stalks (lower part) because the leaves are here too… the root has however a very delicate, earthy flavours… it’s not pungent like the green part. Dig out your coriander roots and freeze them! I also find coriander very moody to grow… Actually coriander roots appear practically in every curry paste I made from David Thompson’s book, so I guess it’s very important. Here Thai/Vietnamese shops sell coriander with roots and I was thrilled recently to discover they decided to sell only roots at lower price! (I guess the leaves were rotten… but the proportion of roots vs leaves is never sufficient, so I made a huge stock of these!).
      I have never used powdered lemongrass or kaffir leaves… so I have no idea how it would work, but let me know if you try. I know frozen Thai produce is always better, but maybe dried is better than nothing. I know you can easily multiply lemongrass if you can find one fresh stalk (let me know, I’ll tell you how).
      How I wish I could send you all these fresh products… (It’s not fair that fresh produce is forbidden by customs!).

  4. FANtastic. Truly one of my favorites. One by one the flavors unfold – yes indeed, the perfection of Thai cuisine. I would eat this soup every day :). Love that you used Thai chili here – I come across so many Thai soups made with Jalapeno and others… but the bird’s eye chili is really unique in Thai cuisine. I wear gloves when I work with them though – dat’s hot!! :D. I wish I had easier access to lemon grass and kaffir lime leaves… my local safeway is one of those where if you’re not looking for potatoes and rice, you’re poop out of luck 😉 (I get tired of driving to Whole Foods for everything). Ooh, you even have the galangal here instead of ginger… Very nice Sissi!

    1. Thank you so much, Kelly for all the compliments. I know you share my passion for Thai cuisine. I am lucky to have access to most seasonings and herbs required in Thai cuisine, so it’s not really my merit 😉 though I do have to visit these shops especially for Thai ingredients. Try freezing kaffir lime leaves, galangal and lemongrass. It’s not as great as fresh, but it works somehow… (for me at least) and since I often buy too much (the packages are too big), I sometimes need to freeze when I see them wilting. Kaffir lime leaves are sold here only frozen recently anyway, so I have no choice. The funny thing is that one of the two biggest chains of Swiss “standard” supermarkets regularly sells bird’s-eye-chillies and lemongrass is there practically every day. How international!

  5. We are huge fans of Thai cuisine and I cook it quite regularly. Yesterday I adapted a mushroom soup that I previously made to more of a Thai inspired soup with kafir lime leaves and coconut milk, it was delicious. I have seen fresh kafir lime leaves here but I usually buy the dried version, it’s quite potent in this form and lasts longer. I always have lemon grass in my freezer, I usually buy a bunch and cut them into 3 cm lengths and freeze for that special moment when I really feel like Thai. I have gotten to the point where I too find restaurant Thai too greasy and heavy so I prefer my interpretation. I also always have fish sauce on hand. I also love adding vermicelli rice noodles to make it a meal. Today we had a lemongrass soup with shrimp (from the freezer). I will check out that cook book you suggest Sissi. Thank you.

    1. Hi Eva, I’m glad you like Thai cuisine too. I must disagree about kaffir lime leaves. I tried to use dried ones and found them much much worse than frozen. Of course it’s better than no kaffir leaves at all! Like you, I freeze lemongrass, galangal and frankly all I can. Above all I prefer of course fresh stuff…Luckily I can buy everything in my city (sometimes I have problems with some products but only because they have run out of it, so all I need to do is be patient and wait for the next shipment which comes every week). I hope you will like David Thompson’s book. It has opened my eyes to how far is the food in all the Thai restaurants I went to from the real thing… Another group of restaurants that has been deleted from my “eating out” list… I think I’ll be soon left with pizzerias only, but I do wish restaurants served better food here…

  6. I love Thai food but have trouble finding all the necessary ingredients in my rural area. I think once we move to Florida, I’ll have a better chance for those illusive food items. Your soup sounds wonderful.

    1. Thank you. I always “slim down” coconut-based Thai recipes. Otherwise I’d eat curries maybe rarely as a special high-calorie treat.

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