- 4 cups all-purpose flour, divided, plus more for rolling
- 1 Tbsp. baking powder
- 1 Tbsp. kosher salt
- 1⁄3 cup canola oil, divided
- 2 Tbsp. toasted sesame oil, divided
- 1 1⁄2 cups thinly sliced scallions, divided
- 1 tsp. crushed red chile flakes, divided
- 1⁄2 tsp. finely ground white pepper, divided
- Soy sauce, for serving
To a food processor, add 2 cups flour and the baking powder. Then, with the motor running, add ⅔ cup cold water; continue processing until a dough forms, about 40 seconds. Transfer the dough to a plate and set aside. Add the remaining flour and the salt to the food processor and, with the motor running, add ⅔ cup boiling water; continue processing until a shaggy dough forms, about 30 seconds. Return the reserved dough to the food processor and pulse until both doughs come together, about 35 seconds.
Lightly flour a clean work surface and turn the dough out onto it. Knead the dough until smooth and elastic, about 4 minutes. Grease a large bowl, transfer the dough to it, cover, and set aside at room temperature until it is pliable, and relaxed, about 2 hours.
Lightly flour a clean work surface and a rolling pin. Split the dough in half, and roll one half out to a 10-by-20-inch rectangle. Brush the rectangle with 1 tablespoon each canola and sesame oil. Sprinkle with half the scallions, half the chile flakes, and half the white pepper. Beginning with one long side, tightly roll the rectangle up like a jelly roll, stretching gently outward as you roll. Cut the roll crosswise into 3 even pieces. Slightly stretch one piece, and starting from one edge, coil it horizontally, tucking the outer end beneath it. Gently flatten the coil into a disk with your hand, then use the rolling pin to flatten the disk further into a 6-inch circle. Repeat with the remaining pieces and the second half of the dough and fillings. Cover the pancakes with a large sheet of plastic wrap and set aside for 10 minutes.
Place a large baking sheet in an oven preheated to 200°F.
To a medium nonstick skillet over medium heat, add 2 teaspoons canola oil. When the oil is hot, add 1 pancake to the skillet and cook, swirling the skillet and turning once, until golden and crisp, about 10 minutes. Use a wide spatula or tongs to transfer the pancake to the baking sheet in the oven. Repeat with the remaining oil and pancakes. When all the pancakes are cooked, remove from the oven and cut into wedges. Serve hot, with soy sauce for dipping.