Odd as it may seem, this really is quite close to the real thing--what you get in the small ranaharn run by Khun Yai (Grandma). Beware cooking school 'enhancements' in Thailand. Khun Yai would probably add straw mushrooms (which go off in 24 hours), some scallions, and might not use celery, but this is very close indeed. 6 dried chillies minimum. Choke dee, khrap!
WOW. This taste like the real thing. I didn't have oyster or fish sauce so I used soy sauce and tamarind sauce with outstanding results. Thanks for posting. Next time I am going to add Thai pumpkin, and sub tofu for the chicken for lunch.