Tangy-Sweet Shrimp Sauce
This sauce is intensely flavored by lots of lime juice, which rounds out the edges of the shrimp sauce (mam tom), a salty, pungent fermented staple of the Viet kitchen. The fish sauce lends savoriness, the chiles add heat, and the sugar softens everything. Although the rice vinegar is optional, it helps smooth out all the flavors. This sauce is the traditional condiment with turmeric catfish with rice noodles (page 226).