U.R. Station
A 20 minute walk from Chong Nonsi BTS, just across from the old immigration bureau, this friendly café serves meals until around 14:00 and cake and pastries until 17:00. There are loads of vegan-friendly baked goods, from cookies to croissants, and everything is freshly baked on a daily basis. Out of the dozen or so pastry options, only two weren't suitable for vegans (and the staff were very keen to point this out without me even asking). This place is highly recommended for acquiring travel snacks for those long bus and train journeys; they do savoury snacks (sesame seaweed!) and sandwiches too.
Tofu with vegetable soup from UR Station (65 baht)
This clear, salty, and celery-strong broth came packed with veggies, mushrooms, and a peppery faux seafood ball, with seaweed for added flavour. Recommended for anyone seeking a light lunch without a spicy kick.
Let Kip eat cake
Coffee Cake from UR Station (55 baht)
The few vegan cakes I've had in Thailand are so mind-blowingly good I have a hard time believing they are dairy free (the creamy frosting layers are to die for)—this was no exception. A rather dense layer cake, this had a mellow coffee flavour and not too much sugar. There were a couple of other cake options as well but coffee will almost always win out when it comes to my appetite.
U.R. Station also does pre-ordered cakes, so if you're local in BKK and are looking for a vegan birthday cake or the like, then check these guys out.
Final Thoughts
Often when I dine out, especially while travelling, I constantly pepper the staff with questions about what's on my plate and the method(s) behind the end result. I probably approached the counter half a dozen times with queries and everyone who worked at the café greeted me each time with a smile and detailed responses. That sort of thing goes a lot way, and combined with good food it leaves more than a positive taste in my mouth about any establishment.