Hemlock

An introduction to true Siam
Word to the wise: Although the vast menu gives novices a great introduction to Thai cuisine, die-hard spice fans may find that the dishes are geared more towards a foreign palate.

Hemlock has garnered quite the reputation on the backpacker circuit as a go-to place for authentic Thai food in traveller-friendly surroundings—but don't let that put you off. Granted, foreigners outnumber locals 10 to one on any given night but this is the only aspect of the restaurant that lacks authenticity.
Dishes such as miang kham (a DIY assembly job of betel leaves which you fill with fish, peanuts, lime, and various other savouries) and khao hor bai bua (rice wrapped in lotus leaf) are about as far from the ubiquitous pad Thai as you can get.