Cut off ends of scallions and slice in half lengthwise, if the scallions are thick, and in the middle if they are too long to fit in the pan.
1 bunch scallions
In a large bowl, mix the flour, cornstarch, salt, garlic, and half of the egg with the ice water. If the batter seems too thick, add a little more water (about 1 teaspoon at a time) until the batter is runny, but still slightly thick.
3/4 cup all-purpose flour, 2 Tablespoons cornstarch, 1 clove garlic, 1/2 teaspoon salt, 3/4 cup ice water, 1 large egg
Heat 2 tablespoons of the oil in a non-stick pan over medium heat, then pour half of the pancake batter into the pan, swirling it into a thin pancake similar to how you would form a crepe. Immediately arrange half of the scallions on top of the batter in a single layer.
4-6 Tablespoons vegetable oil
Drizzle with half of the remaining beaten egg, then cook until the bottom is golden brown (about 3 to 4 minutes), then flip over and cook another 3 to 4 minutes, add more oil, if necessary, until the pancake is crisp and golden brown.
Repeat with remaining batter and ingredients, then serve hot with dipping sauce.