In a large bowl, combine flour and salt. Gradually add hot water, mixing with chopsticks until shaggy. Add cold water and knead for 5-7 minutes until smooth and elastic. Cover and let rest at room temperature for at least 30 minutes.

While the dough rests, prepare the oil paste: In a small bowl, mix 2 tablespoons of vegetable oil with white pepper and half of the finely chopped scallions.

Divide the rested dough into 4 equal portions. On a lightly floured surface, roll one portion into a very thin rectangle (approximately 8x12 inches).

Evenly brush the dough surface with a quarter of the prepared oil paste, then sprinkle with a quarter of the remaining chopped scallions.

Roll the dough tightly from one long side to the other, forming a log. Coil the log into a spiral shape, tucking the end underneath. Gently flatten the spiral with your palm.

Repeat with the remaining dough portions. Cover the flattened spirals and let them rest for another 10 minutes.

Heat 1-2 tablespoons of vegetable oil in a non-stick pan or cast-iron skillet over medium heat. Gently roll one pancake spiral into a 6-8 inch round, about 1/4 inch thick.

Carefully place the pancake in the hot pan and cook for 3-5 minutes per side, until golden brown, crispy, and cooked through. Repeat for the remaining pancakes, adding more oil to the pan as needed.

Serve the Taiwanese Scallion Pancakes hot, cut into wedges, with your favorite dipping sauce.