Dice the chicken into bite-size cubes and place in a large bowl
Add 20ml of soy sauce and the egg, season with salt and pepper, mix well and marinate for 15 minutes
Heat the oil in a deep wok to 180°C (355°F) over medium-high heat
Add plain flour and cornflour to the chicken and toss well to coat
Fry the chicken in batches for 4-5 minutes until golden and drain on a wire rack
Drain most of the oil from the wok, leaving about 1 tablespoon
Finely grate the garlic and ginger, finely slice the chillies, and slice the spring onions keeping white and green parts separated
Place the wok back over high heat and stir fry the garlic, ginger, chilli and white of spring onions for 1 minute
Add remaining soy sauce, ketchup, chilli sauce, vinegar and stock, bring to a simmer
Make a slurry with extra cornflour and 20ml water, add to the wok and stir until sauce thickens and is glossy
Add cooked chicken to the wok and toss through the sauce
Stir through spring onion greens and serve immediately on steamed rice
