Tom kha gai/kai (Thai galangal and chicken soup with coconut milk) is one of my favorite light soups, as in not very dense. I like mine simple with just chicken and mushrooms in a light coconut milk broth. As you can see in the picture, it's more broth than anything else.
Here, I've lifted my spoon so you can see the chicken and mushroom pieces.
You can cross cuisines and serve this like I did with bo luc lac (Vietnamese shaking beef). Or keep it all-Thai and serve it with my pad see-ew (Thai stir-fried soy sauce rice noodles with broccoli, chicken and eggs). Hmm. I need to add more Thai recipes to my repertoire.
Tom Kha Gai (Thai Galangal and Chicken Soup with Coconut Milk)
For a 2-quart pot, you'll need:
1 chicken breast, or thigh, sliced into thin 2-inch strips
1 or 2 cans coconut milk depending on how rich you like your soup
1 can straw mushrooms, drained. Or substitute with regular white or crimini mushrooms, sliced, if you can't find it.
1 knob galangal, cut into big slices, to make it easy to remove later
1 or 2 stalks lemongrass, bruised and cut into big slices, to make it easy to remove later
3-6 Kaffir Lime Leaves, or regular lemon leaves, sliced thinly
fish sauce, to taste
Optional: Lime juice if you want it more sour, sliced chilies if you want it spicy.
On high heat, in a wok, or small soup pot, add a drizzle of oil and saute chicken. The chicken doesn't have to be cooked, just enough to start releasing the juices. Then add 2 cups water, a few dashes of fish sauce, and galangal and lemongrass. When the water boils, turn heat down to medium and allow to simmer for about half an hour or so, so you can get a fragrant broth.
(If you're planning to make the bo luc lac, this would be a good time to get started on that while the soup broth is cooking.)
After the broth has simmered for a while and is properly fragrant, scoop out the galangal and lemongrass. Or you can leave them in if you don't mind fishing them out while you're eating.
Turn heat down to medium low and add a can of coconut milk, or two cans if you really like creamy coconut milk. Taste the soup. Adjust fish sauce to your liking. Add the drained straw mushrooms, or sliced regular mushrooms. Add lime juice if you want it more tart. Add sliced kaffir lime leaves. I've substituted with regular lemon leaves. To make it easy to slice leaves, I simply use a pair of scissors and snip them into the soup pot.
The soup should be creamy and slightly tart and full of lemongrass and galangal aromas.