12 ounces dried spaghetti (or wheat noodles)
3 1/2 tablespoons light soy sauce
3 1/2 tablespoons Shanghai rice vinegar (or seasoned/regular rice vinegar)
1 tablespoon chili oil (75% oil, 25% flakes, or to taste)
1 tablespoon sugar
1/2 to 1 teaspoon Sichuan peppercorn powder
3/4 teaspoon sesame oil
1/2 teaspoon dark soy sauce
1/4 teaspoon salt
1/4 teaspoon MSG (or mushroom powder, optional)
1 clove garlic (very finely minced)
1/3 to 1/2 cup noodle cooking water
1 scallion (chopped)
1 small cucumber (julienned, optional; about 6 ounces/170g)
Cook the noodles according to package instructions until al dente or 1 minute past al dente stage.
Meanwhile, in a serving bowl, add the light soy sauce, Shanghai rice vinegar, chili oil, sugar, Sichuan peppercorn powder, sesame oil, dark soy sauce, salt, MSG (if using), and garlic.
Add the noodles, noodle cooking water, scallion, and cucumber. Toss everything together and serve. If the noodles look dry, add a bit more of the cooking water.