I am not suggesting that this is in any way an authentic Thai curry dish, but it is one which has been enjoyed regularly in our household. It's certainly better than those "cook-in sauces" you can buy in jars from the supermarket!
I tend to cook this dish with leftovers from a roast chicken, by paring the remaining meat away from the bones, and then boiling up the carcase, bones and skin (about 20 minutes in just enough water to cover) to make the stock. Alternatively, you could just use skinless chicken breasts and a chicken stock cube.
Boil up a pint of chicken stock in a large saucepan. You might like to add a tablespoon of Thai fish sauce, or perhaps a fish stock cube at this point.
If you can get it, add a whole stick of Lemongrass to the stock. (I tend to use the preserved stuff available in jars from the supermarket.) Also, a couple of dried Kaffir Lime leaves give an authentic touch here. Also add to the stock three or four spring onions, chopped coarsely.
Now, decision time! How many chillis to add? This is a matter of taste. I like my food tangy, rather than blisteringly hot, so I use a couple of red birdseye chillies, chopped finely and with the seeds removed. (Don't touch your eyes or mouth while chopping chillis.) Add more chillis at your own risk!
Now add the chopped chicken meat. You can also add a few button mushrooms, chopped in half, at this point. Boil until the meat is cooked through. Carefully remove the kaffir lime leaves and the lemongrass stick.
The traditionally green colour of this dish comes from the combination of coriander leaves (also known as cilantro) and coconut. Add a tablespoon of dried coriander (yes, lots!) to the boiling stock, and stir in well. Allow to simmer for a couple of minutes, then add a couple of ounces of creamed coconut paste and stir in well. You should now have a creamy green sauce.
This dish is now almost ready. If you like your sauces runny, you can serve it as-is, or stir in a teaspoon of cornflour (disolved in a little water) to thicken it slightly. Serve with cardamom-flavoured rice.