Scallion Pancakes

To Make Pancakes:

• To make the pancakes: Place 2 cups (300 g) of the flour in the bowl of a stand mixer. Slowly drizzle in the boiling water while stirring with a pair of chopsticks (or a fork). Mix until the water is fully absorbed, and the dough forms flakes without a lot of dry flour on the sides of the bowl. Attach the dough hook to the mixer and turn on the mixer, gradually increasing to speed Set a timer for 5 minutes. If the dough is too wet and cannot be lifted from the bottom of the mixer, sprinkle in a bit of flour, 1 teaspoon at a time, until it forms a ball. The dough should be semismooth with no dry flour left on the bowl. Cover with plastic wrap and let rest for 30 minutes to 2 hours. Move it to the refrigerator if storing for longer.
• While the dough is resting, combine the remaining 2 tablespoons flour, peanut oil, salt, and Sichuan pepper (if using) in a small bowl for the oil paste. Mix until a smooth paste forms.
• When the dough is done resting, it should be very smooth. Lightly grease a work surface with some peanut oil. Divide the dough into 2 equal-size pieces using a knife or dough cutter. Roll each half into a long log, then cut each log into 3equal-size pieces for 6 pieces total. Work with one dough piece at a time and cover the rest with plastic wrap to prevent drying out. Place a dough piece on the work surface and flatten it as much as you can into a disc. Use a rolling pin to roll the disc into a thin rectangle approximately 12 inches (30 cm) long by 8 inches (20 cm) wide.
• Drizzle 2 teaspoons of the oil paste on the dough. Use a brush or the back of a spoon to spread the oil so that it covers the dough evenly and completely. Sprinkle 2 tablespoons scallions evenly over the paste. Roll up the dough from each of the long sides toward each other until the two sides meet. Smooth out the dough using your fingers, squeezing out as much air as you can. Hold the two ends with your hands and gently stretch the dough log 2 to 3 inches (5 to 7.5 cm) with out tearing the dough. Roll up the dough log from both ends toward the center, until they meet. Lay one dough coil on top of the other one so that they are stacked. Gently press them together and transfer to a large plate or tray. Cover with plastic wrap to prevent drying out. Repeat with the remaining dough. Let the dough rest for 15 minutes. Using a rolling pin, roll each coiled piece into a circle, about ¼ inch (6 mm) thick, then stack them with a piece of parchment paper between each one. Cover and let rest for another 15 minutes.
• To make the dipping sauce (if using): In a small bowl, combine the soy sauce, vinegar, and sugar with 1 tablespoon of water and mix until the sugar is dissolved.
• Heat a 9-inch (23 cm) cast-iron pan (or nonstick skillet) over medium-high heat and add 1 tablespoon vegetable oil. Once the oil is hot, add a pancake. Cover the pan and reduce the heat to medium. Let the pancake cook, covered, for 2 minutes, until the bottom turns golden. Remove the lid, drizzle about 2 teaspoons vegetable oil on top of the pancake, flip, cover, and cook for 1 to 2 minutes more, until the bottom turns golden. Transfer the pancake to a large plate to cool slightly. Repeat to cook as many pancakes as you plan to serve.
• Serve hot with dipping sauce (if using).
• To store scallion pancakes, stack them in a resealable plastic bag with parchment paper in between each pancake. Store in the refrigerator for up to 3 days or in the freezer for up to 3 months. To reheat, heat a lightly oiled nonstick pan over medium heat, add a pancake, and cook, flipping occasionally, until the pancake is warm throughout. You can also heat them up in the oven at 350°F (175°C; gas mark 4) for 10 to 15 minutes. If frozen, thaw them overnight in the refrigerator before reheating.
• If freezing: You can freeze uncooked pancakes after they are rolled out and rest in step 4. Transfer the pancakes to a resealable plastic bag using parchment paper to separate them. Squeeze out as much air as possible and seal the bag. They can be frozen for up to 3 months. To cook, let them thaw for 10 minutes, then cook the how you would cook fresh ones.