Mix the stock or water, fish sauce, oyster sauce, sugar and cornflour in a small bowl until smooth.
Dry-fry the cashew nuts in a nonstick frying pan on a low heat. Shake the pan to move them around for 8–10 minutes or until lightly browned. Remove from the pan.
Heat 1½ tablespoons of oil in a wok and stir-fry the chillies over a medium heat for a few seconds. They should darken but not blacken and burn. Remove and drain on kitchen paper. Heat the remaining oil in the wok, adding extra if required, and stir-fry the garlic for 1–2 minutes or until lightly browned. Add the chicken and stir-fry for 4–5 minutes. Add the carrot, pepper and onion and stir-fry for another 3–4 minutes.
Stir the sauce mixture, pour it in and stir-fry together for another minute or so. Taste and adjust the seasoning. Add the cashew nuts, chillies and spring onions. Sprinkle with ground black pepper and toss well.
Spoon on to a warm serving plate and garnish with coriander leaves.