This is my adaptation of the Cook's Illustrated recipe. Best with the tamarind but you can sub out 1/3 lime juice + 1/3 cup water. It's still good but not AS good. You must prepare everything before you start cooking or it gets chaotic! You can sub out boneless, skinless thighs.
For more authenticity, you can add 3 c. bean sprouts, 2 T dried shrimp and 2 T Thai salted radish but I either don't like them or don't have them on hand and think it works fine without. If you want to add them add in step 15. Also, if you want to add fish sauce, add 3 T to the sauce mixture.