Prep the vegetables: Peel the lotus root and eggplant, then slice into even pieces no thicker than 1cm. For easy assembly, you can cut "clip-style" slices (nearly through on the first cut, fully through on the second) or simply cut separate flat slices to pair up. Uneven thick slices will leave the center undercooked, so keep sizing consistent.
Season the pork filling: Add cooking wine, light soy sauce, oyster sauce, white pepper and salt to the ground pork. Stir steadily in one direction until the mixture turns sticky and well-combined — this technique gives the filling a bouncier, juicier bite
Assemble the sandwiches: Spread a thin, even layer of pork filling onto one lotus root slice, then press a second slice on top to seal. Do not overstuff — excess filling will ooze out during cooking and prevent the batter from adhering properly. Repeat with all lotus root and eggplant slices
Mix the batter: Whisk together eggs, all-purpose flour and a small splash of cold water until completely smooth with no lumps. The ideal batter coats the back of a spoon and drips slowly when lifted. Too thin and it will slide right off the vegetables; too thick and the crust will turn heavy and doughy.
Coat each sandwich: Dip every assembled lotus root sandwich fully into the batter, turning to cover all sides evenly. Let excess batter drip off for a few seconds before placing in the air fryer basket.
Air fry to crisp perfection: Preheat your air fryer to 180°C (356°F) for 3 minutes. Arrange battered sandwiches in a single layer, leaving gaps between each piece for even air circulation. Cook for 10 minutes, then carefully flip each sandwich and cook for another 10 minutes, until the batter is deep golden and crisp all around