Whisk the all-purpose flour, potato starch, and salt together in a large mixing bowl.

Pour in the ice cold water and beaten egg, mixing gently until just combined. Be careful not to overmix.

Add the chopped spring onions into the batter and toss lightly to coat.

Heat the vegetable oil in a large non-stick skillet over medium-high heat until shimmering.

Pour the batter mixture into the skillet, spreading the spring onions out evenly with a spatula to form a flat, round pancake.

Fry the pancake undisturbed for 4 to 5 minutes until the bottom is deeply golden brown and crispy.

Carefully flip the pancake and cook the other side for an additional 3 to 4 minutes until fully cooked and crisp.

Transfer the pancake to a cutting board, slice into wedges or squares, and serve immediately with a soy dipping sauce.