Biang Biang Noodles

In a stand mixer fitted with a dough hook, combine the dough ingredients and blend on medium speed until dough comes together, 8 to 10 minutes. You may need to add more water by the teaspoonful to form a firm but uniform dough. Remove dough from mixer and knead on a lightly floured surface until smooth, about 4 minutes. Form the dough into a flat rectangular shape, wrap in plastic, and let dough at room temperature, 1 to 2 hours.

On a lightly floured surface, cut dough into five equal pieces. Using a rolling pin, roll out each piece into an oval shape, around 1/4 inch thick. Brush oil onto each piece of dough, stack them, wrap again in plastic, and refrigerate for 30 minutes. Let the dough rest at room temperature for 30 minutes more.

Meanwhile, pulse the chili flakes in a spice grinder until well ground, about 1 minute.

Working with one piece of dough at a time and keeping the rest covered, make an indent with a chopstick vertically on dough. Taking both ends, gently pull noodle and swing (like a jump rope), allowing the middle of the noodle to slap the work surface with each rotation. After the noodle is tripled in length, pull apart from center of the noodle to thin out the noodle, but do not pull apart—this should be one connected strand of noodle. Keep bouncing the noodle for a few more seconds. Set the noodle down on a lightly floured work surface; repeat with the rest of the dough.

ring a large pot of salted water to a boil. Drop noodles in, give them a stir and cook until they rise to the top, 1 to 2 minutes. Drain the noodles and transfer them to a large serving bowl; top with garlic, ginger, scallions, ground chile, cumin, coriander, and salt. Do not stir; set aside.

In a small saucepan, heat oil over medium-high until it reaches 275ºF on an instant-read thermometer. Pour oil over noodles and stir together until evenly blended. Serve immediately.