Peel the 4 bulb onions and cut them into half rings.
Cut the 1.5 kg chicken into portions.
In a bowl, combine the chicken pieces, soy sauce, salt, and pepper. Add the onion half rings and mix for 2 minutes until thoroughly combined.
Cover and refrigerate the marinating chicken for 40 minutes.
Heat a pan or grill to medium-high heat.
Cook the chicken in the pan or on the grill until the internal temperature reaches 74 °C / 165 °F, approximately 20-30 minutes depending on portion size.