Grate celeriac root on the large side of a box grater. Transfer to a bowl, squeeze over lemon juice and mix well.
Combine mayonnaise, dijon, green chilli, soy sauce, parsley and spring onion. Stir through grated celeriac. Taste and season with salt and pepper as needed.
Using a meat mallet, carefully flatten chicken fillets down to approx 1cm thickness. Season with salt.
In a large bowl, combine egg, ginger, garlic and soy sauce. Place the chicken fillets into the egg mix and coat well.
Combine rice flour and cornstarch then add it to the chicken-egg mixture. Working quickly, massage the flour into the chicken to create a thick batter.
Pour enough oil into a frying pan to reach a depth of ½ centimetre. Heat the oil to approximately 170°C. To test if the oil is ready, drop in a few salt flakes or breadcrumbs; if they rise to the surface and bubble gently, the oil is at the right temperature.
Add chicken schnitzels to the oil and fry for a few minutes on each side until the outside is browned and crispy and centre cooked through.
Remove the schnitzels from the pan and set aside to rest for a few minutes. Using some of the remaining oil, crack in the eggs and fry until the edges are golden and crispy. Season with a pinch of salt.
Divide celeriac remoulade between plates, layer over karaage schnitzels and top with a fried egg. Garnish with black sesame seeds.