Preparation

• Preheat the oven to 200°F. Line a large baking sheet with paper towels. You will keep the pajeon warm in the oven on the baking sheet while you cook them in batches.
• Make the dipping sauce: In a small bowl whisk together the soy sauce, vinegar, scallion whites, sesame oil, sugar, and sesame seeds. Whisk in the gochugaru if you would like a little heat. Set aside.
• Make the batter: In a large bowl, whisk together the all-purpose flour, rice flour, salt, garlic powder, onion powder, and baking powder. Add 1 ½ cups water, egg, and sesame oil, and whisk until evenly combined. The batter should be thin and runny—add more water, 1 tablespoon at a time, as needed. Allow the batter to rest while you prepare the scallions.
• Prepare scallions: Cut off and discard the root end of the scallions. Cut them in half crosswise, making 3- to 4-inch pieces. Cut the whites and any thicker green parts in half lengthwise. Separate the scallions into 4 even piles.
• Cook the pajeon: Place a large nonstick pan over medium-high heat. Add 2 tablespoons oil and ¼ of the sliced scallions in a single layer into the pan. Pour about ½ cup of batter evenly over the scallions, making sure to fill the gaps. Cook for 3 to 4 minutes, until the underside is golden brown and crispy. Scoot a long thin spatula fully under the pajeon and flip. Cook the other side for 3 to 4 minutes, until browned. Transfer the pajeon onto the prepared baking sheet and keep warm in the oven while you make the remaining pajeon. Add a couple of teaspoons of oil to the pan before each new batch.
• Serve the pajeon: Slice the pajeon into wedges or squares and serve with dipping sauce on the side. Cooked rice and kimchi are delicious accompaniments too!
• Allow leftovers to fully cool and refrigerate wrapped in plastic wrap or in zip top bags for 3 to 4 days. To freeze, separate the pajeon with pieces of parchment paper and store in a freezer bag for up to 1 month. Defrost overnight in the refrigerator before reheating. To reheat, place in a nonstick pan over medium heat until warmed through.