Preparation In a large bowl, add the flour and salt and mix well to combine. Add the room-temperature water slowly while mixing the dough with your hands. Using both hands, knead the dough until it comes together in a smooth ball, 3 to 5 minutes. When the dough is formed, cover the dough with plastic wrap and let it rest at room temperature for 20 minutes. After resting, remove the plastic wrap and knead the dough in the bowl a few more times. Cover again with plastic wrap and let it rest for another 15 minutes. After the second rest, brush a bit of the oil on the dough and place it on a cutting board or work surface. Cut the dough in half, and using your hands, roll each piece of dough into a long, snake-like cylindrical shape, a little over 1⁄2 inch (12 mm) in diameter. Lightly coat a large container with oil. Store the dough inside by forming each piece into a spiral (like a resting snake). Brush the dough with a bit of extra oil to prevent sticking. Cover it with plastic wrap and rest in the refrigerator for at least 30 minutes (if using immediately) or up to 1 day. When ready to use, remove the dough from the refrigerator and let it rest at room temperature for 10 minutes. Fill a large pot with water, enough for the noodles to swim freely in. Set the pot over high heat and bring to a boil. Work with one coil of dough at a time. Pick up one end of the dough coil with one hand, then grab it about 4 inches (10 cm) down the strand with your other hand. Using your first hand, pull the end of the dough out and away from your second hand, to stretch it without breaking it. Continue pulling the dough with your first hand, stretching it out with the other. This should lengthen and slim the dough without breaking it. After you have finished stretching the length of the noodle, the dough should be less than 1⁄2 inch (12 mm) in diameter, roughly 8 feet (2.5 m) long. Loop the dough into a large ring roughly 18 inches (46 cm) in diameter. You might have to loop the dough several times. With your hands shoulder-width apart, pick up the dough ring with both of your hands, cradling it with your fingers. Make sure not to tangle the strand. With both hands holding the dough, pull the noodle ring outward while slapping it up and down on the work counter. Pull until the individual strand is less than 1⁄4 inch (6 mm) in diameter. (You could go thinner, but it requires skill.) Be careful not to break it; if the noodle snaps, simply pick up where the strand breaks and resume pulling. Each noodle should end up being roughly 27 feet (8 m) long. Repeat the stretching, pulling, and slapping process with the second half of the snake coil. Once done pulling both pieces of dough, throw the noodles into the boiling water right away, stirring so the noodles don’t stick to themselves or the side of the pot. When the water comes back to a rapid boil, pour 1 cup of cold water into the pot. Bring back to a boil and cook for 1 minute before adding another cup of cold water. Once the pot boils again, carefully fish out the noodles using a hand strainer or spider. The noodles should have boiled for 2 to 3 minutes in total. Excerpted from Xi'an Famous Foods: The Cuisine of Western China, from New York's Favorite Noodle Shop by Jason Wang with Jessica Chou, copyright © 2020. Published by Harry N. Abrams.Buy the full book from Amazon or Bookshop.