This is an authentic recipe for Cantonese lemon chicken. Mix the egg, water, soy sauce, rice wine and the 3 tsp cornflour in a small bowl until smooth. Pour this mixture over the chicken, mix well and set aside for 10 minutes.
Pre-heat the oven to 180C.
Sift the extra cornflour and plain flour together onto a plate. Roll each piece of chicken in the flour, coating each piece evenly and shake off the excess. Place the chicken in a single layer on a plate ready to be fried.
Heat the oil for deep-frying in a wok or large pan. When it is hot enough, fry the chicken in batches until it is a light golden colour. Remove with a slotted spoon and drain on kitchen paper. Arrange in one layer on a baking tray and transfer to the oven where it will finish cooking while you make the sauce.
To make the lemon sauce:
Combine the lemon juice, the 2 tbsp water, sugar and rice wine in a small pan. Bring to the boil, stirring until the sugar dissolves. Stir the cornflour into the extra tablspoon of water and mix to a smooth paste. Add it to the lemon juice mixture, stirring until the sauce thickens slightly. Arrange the chicken on a serving plate.