Out of the five times I've tried to go here, it's only been open once, so I have no idea what kind of business they're running, but the food is great. It's northern Thai. We had the northern sausage, curry, papaya salad, chilli dip and laab. I enjoyed it all and would recommend it if you're lucky enough to find it open.
"One of the most famous dishes in this tradition is laab, a punchy, smokey (in some cases raw) mincemeat, offal and blood salad; another is nam prik ong, a tomato pork dip akin to a ragu – excellent versions of both are made by the sisters of Sorn Chai restaurant, opposite Thapae Gate"
— From Guardian article