• Rice sticks, or banh pho, are translucent, linguini-shaped dried noodles sold in Asian markets. For pho, buy the small, 1/16-inch-wide variety. To prepare them, first soak them in cold water for 30 minutes and drain. Then bring a large pot of water to a rolling boil. When you're ready to serve (not before), place the noodles, one portion at a time, into a sieve and lower it into the boiling water. Using chopsticks or a long spoon, stir so the noodles untangle and cook evenly. Blanch just until they're soft but still chewy, about 10 to 20 seconds. Drain completely, then transfer to a preheated bowl. Cook the remaining noodles the same way. If you're cooking for several people, you may also cook the noodles all at once by adding them directly to the pot of boiling water. Just make sure to serve them immediately. • The Vietnamese believe that "a meat dish should taste like a meat dish," says Pham. Cooking the meat with vegetables would distort its flavor, so all veggies (except for aromatics like ginger and onion) are added after cooking. Since Vietnamese food is so simply prepared, using the freshest, highest-quality ingredients is essential. Pham recommends seeking out organic, antibiotic-free meat and purchasing it on the same day you plan to use it to ensure freshness. • Fish sauce (nuoc mam), a pungent, salty liquid made from fermented anchovies, adds depth and flavor to numerous Vietnamese dishes. For best results, choose bottles priced at $3 to $4 rather than $1, and pass on jars that are dark, which indicates oxidation or the presence of additives. "Look for fish sauce in glass jars. Avoid plastic," says Pham. "The fish sauce should have a nice, even color, like iced tea." She suggests Three Crabs, Lobster Boy, and Phu Quoc brands. When cooking with fish sauce, always add it to other liquids: Never place it directly in a hot, dry pan, which would broadcast its pungent, fishy odor throughout your kitchen in a less-than-pleasant way. Soy sauce is an acceptable vegetarian substitute, though it does lack fish sauce's smoky complexity. • When prepping ingredients for Vietnamese cooking, Pham recommends cutting everything into small, even sizes, which cook more quickly and evenly. A mandoline makes quick work of the paper-thin slices of onions that top this soup. • Asian basil, also called Thai or holy basil, has a delicate anise flavor. Regular (sweet) basil does not make a good substitute, as it's too strong. "Use mint instead," says Pham. Saw-leaf herb has a floral, cilantro-like flavor and three- to four-inch long, dark-green leaves with serrated edges. Cilantro or Asian basil make good substitutes. Both herbs can be found in the produce section of Asian grocery stores or in farmers' markets. • The Thai bird chile, a short, narrow, pointed, green or red variety, is not exclusively Thai — it's also the Vietnamese hot pepper of choice. "In Vietnam, we just call them peppers," says Pham. Thai bird chiles can be found at Asian grocery stores and better supermarkets, or ordered from Asian foods supplier Uwajimaya at (800) 889-1928. If you can't find them, Pham suggests substituting fresh red serrano chiles, which are hotter and sweeter than their green counterparts.