We moved to Hanoi earlier this year and this restaurant is about 10 minutes' walk away from our apartment... so we eat here all the time. The food is great and the family who run it are very kind and friendly. Favourites on the menu include: Lau Thai (Thai hot pot); Pho Ga (chicken noodle soup); chicken legs; eggplant in clay pot; lemongrass tofu. Their set menu at lunchtime is very good. Plus they make good fresh juices.
They also have a small supply of products for sale (fish sauce, dried meats, broth mixes, etc).