Cut the chicken into small strips, place in a bowl, and add all the marinade ingredients. This technique, where baking soda and/or cornstarch are added to the chicken, is called "velveting," and it makes the chicken super tender. Let it sit for about 15 minutes at room temperature.

In another bowl, mix all the sauce ingredients and set aside.

Heat oil in a wok or pan, add the sliced leek, and stir-fry for a few minutes.

Add the chicken and stir-fry until it turns golden brown and cooked through (depending on the size of the pieces and the cut of meat, usually about 5 minutes).

Pour the sauce over everything and simmer for 2 minutes. Taste and adjust seasoning if necessary.

Sprinkle with roasted peanuts and serve with rice.