Fish sauce is a condiment made from fermented fish that is commonly used in Thai and Vietnamese cooking. It is salty like soy sauce, but has a more complex flavor. Stir fries with fish sauce should be seasoned with herbs and flavorings characteristic of Southeast Asian cuisine, such as Thai basil, cilantro and lime. They should also be lightly cooked, making the most of the stir fry technique, which cooks ingredients hot and fast.
Mince the garlic and ginger into pieces no larger than grains of rice. Cut your onion into pieces the size of peas and all other vegetables into bite-size pieces.
Heat the vegetable oil in your wok. Place a small piece of onion or garlic in the oil; if it hisses gently, the oil is the right temperature. If the oil smokes or the piece of onion or garlic browns almost immediately, turn off the heat for a minute or two, and then test it again.
Add your meat to the oil, and cook it for a few minutes, stirring almost constantly. Season it with a little bit of fish sauce, enough to coat it but not enough to collect in the bottom of the pan.
Add your onion, garlic and ginger, and cook for a few minutes longer, stirring almost constantly, until the onion is translucent.
Add your green beans and broccoli, and cook for a few minutes longer, stirring almost constantly, until the vegetables are just tender. Season them with a bit more fish sauce, enough to coat them but not enough to collect in the bottom of the pan.
Turn off the heat, and add lime juice, Thai basil and more fish sauce if you want your stir fry to be saltier. Mix well.