Chef Kim’s version of this popular appetizer is full of greens held together by a crisp matrix of batter. He'll share the secrets to making a light, airy pancake: ice cold club soda and good technique.
Batter: In a large bowl, add flour, cornstarch, baking powder, salt, sugar, and pepper. Mix well and set aside. In another bowl, add egg yolks, club soda, and soy sauce. Smash and peel the garlic, then finely chop. Use the flat part of your knife to press down on the garlic to further break it down, then continue to mince. Place garlic in the bowl with the wet ingredients. Add the wet ingredients to the dry and gently whisk, just enough to combine. (Do not over-whisk, or you will form extra gluten in the batter, making it too doughy.) Cover with plastic and let rest in the refrigerator, allowing any small lumps in the batter to dissolve, 10–15 minutes.
Trim and discard scallion roots and the very tips of the greens. Slice scallion greens into 1½-inch batons; cut the denser white parts slightly shorter, about 1 inch. Chop the Chinese chives into 1-inch batons. Combine chives and scallions in a bowl.
Dipping sauce: In a small bowl, add soy sauce, sesame oil, mirin, and rice vinegar. Stir to blend. Reserve at room temperature until ready to use. Makes about ¼ cup. (Note: Dipping sauce can be made several days ahead and stored in a lidded container in the refrigerator. Bring to room temperature before using.)
Heat skillet over high heat. Remove batter from refrigerator and quickly whisk, about 10 seconds. Ladle just enough batter into the scallions and chives to hold them together; mix with your hand until every scallion and chive is coated with batter. (You will have leftover batter.) Add ¾ of the oil to the hot skillet, enough to cover the bottom in a thin layer. When the oil is rippling, add the pancake mixture: spread it in an even layer across the skillet, without letting it touch the sides of the skillet. (Otherwise, the edges will burn before the center is cooked through.) Ladle another ½-cup batter across the top of the pancake and cook until it’s golden brown on the bottom, 2–3 minutes. Lower the temperature if the pancake is browning too quickly.
Gently slide a spatula (or two, if necessary) under the pancake and flip it, using caution to avoid oil splatter. Cook 2–3 more minutes, flattening the top with spatula, and occasionally shaking the skillet so some of the hot oil runs underneath the pancake. Add more oil as necessary to maintain a thin layer in the skillet. When the bottom is a deep golden brown, flip one more time and cook another 2 minutes.
Remove pancake from skillet and transfer onto several layers of paper towels to drain excess oil. Cut pancake into 6 wedges, like a pizza, and serve immediately with dipping sauce. (Note: Extra batter can be stored in an airtight container in the refrigerator for several days; make another pancake using scallions or any seasonal leafy green.)