If you don't feel like tracking down galangal, lemongrass and kaffir lime leaves you can get close to an authentic tom ka gai with these ingredients.
**FIRST OFF** This is a MOCK version of true Tom Ka Gai soup. However...the taste is very close to the real deal WITHOUT needing "hard to find" ingredients. We loved the ease of the recipe. TALK ABOUT A QUICKIE. My changes: NIX the turmeric - it made the soup sooo bright yellow! I almost doubled the lime juice. I put in the required amount and then floated a few thick lime slices on top while it simmered. I removed those before serving it. I probably doubled the Cilantro. I put some in while it simmered, and put more in just before serving. Instead of water I used low sodium/low fat chicken broth to round out the flavor. I added just enough Splenda Sweetner to “sweeten it up” just a little . I’ve had this soup served both ways ( slightly sweet, and no sugar at all). We prefer it slightly sweet. "Sweet" just ROCKS the flavor of the lime! I have never found Lemon Grass locally, so I quit worrying about it. The soup was EXCELLENT and almost a DIRECT HIT for what we have eaten in upper end Thai restaurants. Do yourself a favor...and DO NOT SMELL THE FISH SAUCE. It's PUTRID AND DISGUSTING! However...once mixed with the other ingredients something magical happens and it was beyond wonderful when all the flavors commingled! I like to put a small scoop of white rice into a bowl and add the soup over that. Next time I make it I'm going to try using 1/2 lemon juice -1/2 lime juice. Will definitely make this again for company! - 08 Sep 2007 (Review from Allrecipes USA and Canada)
First of all, 'Kah' is galanga in Thai. Traditionally, 'Tom Kah' soup is predominantly flavored with three essential ingredients, namely galanga, lemongrass, and kaffir lime leaves, in which this recipe lacks. For a vegetarian soup simply substitute chicken with oyster mushroom. Galanga, lemongrass and kaffir lime leaves add flavour to the soup and are pretty to look at in the bowl, but they are inedible. I often remove these ingredients by straining, then cook the meat or mushroom in the soup. - 10 May 2001 (Review from Allrecipes USA and Canada)
When I made this following the recipe exactly I thought it tasted horrible. Then I added lemongrass and let it infuse with the chicken and left out the tumeric (coconut soup should be white). Finally, I remembered when I took a cooking lesson from a Thai chef, she said to always always add sugar when using fish sauce. I forgot the exact proportion by went by taste (had to add quite a lot). Voila! Now it's perfect. - 26 Jan 2006 (Review from Allrecipes USA and Canada)