You will find this condiment on the table at most Thai and Vietnamese restaurants. It is just the thing to add depth, salt, and heat to bowls of Pho Bo and dishes like Thai fried rice noodles (Kuaytiaw Khua Kai).

Combine in a small bowl:

Let sit for at least 30 minutes to give the chiles time to infuse the fish sauce, then use immediately or refrigerate for up to 1 week.