If you don't mind trying street food and you have only 10,000Vnd in your pocket, then this lunch is for you. That's fried tofu with noodles. This is served at a very popular place in Phat Loc lane near the corner of Hang Be, Hang Bac and Hang Mam street. There's no air conditioning but an old electric fan hanging on the wall is included with the price :) The sauce may be a problem for you. It is a smelly shrimp sauce which I love but I know many westerners don't like it and prefer normal fish sauce.
old lady in front of this shop. She serves very good tea with clean ice and in clean glasses. I am sure that you won't have any trouble with your stomach.
Ngo Phat loc