For the chicken:
For the stir fry:
For the chicken, place the egg into a bowl, add the cornflour and a pinch of salt, and whisk well to combine. Then add the chicken to the egg mixture and coat well.
Heat a wok until smoking and add the groundnut oil. Fry the chicken for 4-5 minutes, or until golden-brown and crisp, then remove with a slotted spoon and drain on absorbent kitchen paper.
For the stir-fry, pour off all the oil from the wok, except for one tablespoon. Reheat the oil over a high heat, add the onion, and stirfry for a few seconds.
Add the yellow and red pepper slices and stirfry them for 1 minute, or until softened. Then add the chicken pieces and stir-fry them for a further 1-2 minutes. Finally, add the stock and soy sauce and simmer for another minute, or until the chicken is cooked through.
Stir in the spring onions and cashew nuts, season to taste with sea salt and ground white pepper, and transfer it to a serving dish.
Serve immediately with steamed rice.