Cut the chicken into uniform pieces. If the chicken is one inch thick, the onions should be cut a bit smaller.
If the onion is thicker than the chicken, then the meat won't get into contact with the heat source. Direct contact is necessary for the meat to caramelize and get that nice brown color and hearty flavor.
When putting the ingredients on the stick, start with an onion slice, and continue with a sage leaf, chicken, sage, onion pattern.
Sprinkle with salt and pepper.
When cooked, the ingredients fuse together and create a superb flavor.