Peel and finely dice the onions. Clean the leek, cut lengthwise, wash and cut into thin rings. Clean and wash the chillies and cut them with the seeds into very thin rings.
Wash the chicken filet, dab dry and cut into pieces. Season with salt and pepper. Mix with the starch.
Heat the oil in a wok or large frying pan. Fry the meat in it at medium heat all around for about 5 minutes. Stir in the onions and chilli and continue to fry for 3-4 minutes. Stir in the leek and fry for 1 minute.
Stir in mayonnaise, soy sauce and fish sauce. Jasmine rice tastes good with this.