This recipes is part of Chinese Restaurant Appetizer Week Perhaps the biggest key to making excellent Dan Dan Noodles is to make your own roasted chili oil. When done right, it get a rich, fruity, smoky flavor that none of the store-bought stuff can touch. It really quite simple. Just toast a handful of whole Chinese chilis (or if you want, red pepper flakes) in a dry skillet until ever-so-slightly smoking. Transfer them to a food processor with a cup of neutral oil, like canola, and whiz the whole thing up. Let it sit in a sealed container in the fridge for a week or so, and you're good to go. You can even top up the jar with more oil and toasted chilis every time you seem to be running low. Make some, have it on hand at all times, and it will revolutionize your mapo tofu, ramen, dumplings, stir-fries, and countless other dishes. Chinkiang vinegar is a dark Chinese vinegar with a mildly sweet flavor. If you can't find it, you can substitute it with an equal-part mix it rice vinegar and balsamic vinegar. Preserve Sichuan Vegetable (zha cai) is pickled mustard root available in cans or jars in most Chinese markets. Carefully remove any dark seeds or stems from Sichuan peppercorns before using. Use only the textured husks. Toast in a dry skillet over medium-high heat until fragrant (about 30 seconds) for best results.