Food sits at the very centre of Vietnamese culture: every significant holiday on the Vietnamese cultural calendar, all the important milestones in a Vietnamese person's life, and indeed, most of the important day-to-day social events and interactions - food plays a central role in each. Special dishes are prepared and served with great care for every birth, marriage and death, and the anniversaries of ancestors' deaths. More business deals are struck over dinner tables than over boardroom tables, and when friends get together, they eat together. Preparing food and eating together remains the focus of family life.
Vietnamese cuisine varies slightly from region to region, with many regions having their own specialities. Generally, northern Vietnamese cuisine is known for being bland while southern Vietnamese cuisine is known for being spicy.
At the same time, the Vietnamese are surprisingly modest about their cuisine. (And old proverb/joke says that a fortunate man has a Western (French) house, Japanese wife, and Chinese chef.) High-end restaurants tend to serve "Asian-fusion" cuisine, with elements of Thai, Japanese, and Chinese mixed in.
The most authentic Vietnamese food is found at street side "restaurants" (A collection of plastic outdoor furniture placed on the footpath), with most walk-in restaurants being mainly for tourists. Definite regional styles exist -- northern, central, and southern, each with unique dishes. Central style is perhaps the most celebrated, with dishes such as mi quang (wheat noodles with herbs, pork, and shrimp), banh canh cua (crab soup with thick rice noodles) and bun bo Hue (beef soup with herbs and noodles).
In rural and regional areas it is usually safest to eat the locally grown types of food as these are usually bought each day from the market. It is not uncommon, that after you have ordered your meal a young child of the family will be seen running out the back towards the nearest market to purchase the items.
Most restaurants/cafes in Vietnam will have a bewildering variety of food available. It is very common for menus to be up to 10-15 pages. These will inlcude all types of vietnamese food, plus some token western food, possibly some chinese and maybe a pad thai as well. It is generally best to stick with the specialty of the area as this food will be the freshest and also the best prepared.
Vegetarian food is quite easy to find anywhere in Vietnam due in large part to the Buddhist influence. These restaurants will run from upscale to street stall. Basically any Vietnamese dish with meat can be made vegetarian with the abundance of fake meats. Besides the Buddhist influence of 2 vegetarian days a month, Cao Dai people eat vegetarian 16 days, and followers of the bizarre Quan Yin method eat vegan daily. Look for any sign that says Com Chay or simply remember the phrase An Chay.
Coffee, bread and pastries
Coffee, baguettes, and pastries were originally introduced by the French colonials, but all three have been localized and remain popular contemporary aspects of Vietnamese cuisine. More on cà phê below, but coffee shops that also serve light fare can be found in almost village and on multiple street corners in the bigger cities.
Bánh mì Hanoi are French bread sandwiches: freshly baked white bread baguettes filled with grilled meats or liver or pork pâté, plus fresh herbs and vegetables. Most pastry shops serve a variety of sweets and quick foods, and are now owned by Vietnamese.
If you like seafood, you may find heaven in Vietnam. The ultimate seafood experience is traveling to a seaside village or beach resort area in the south to try the local seafood restaurants that often serve shrimp, crab, and locally-caught fish. Follow the locals to a good restaurant: the food will still be swimming when you order it, it will be well-prepared, very affordable by Western standards, and often served in friendly surroundings with spectacular views.