Pre-heat oven to 200C/400F with fan assist if your oven has this feature.
Mix together lemon juice, oil, and all the spices.
Butterfly each chicken breast. Pound out any pieces that are really thick.
Put marinade and chicken into a large ziploc bag or container.
Refrigerate for a minimum of 2 hours. Ideally for 4-6 hours.
Cut the onion in half, place it flat side down on your baking dish, and push the skewer into the onion so it is standing up and secure.
Start layering your chicken breast onto the skewer. Adjust the chicken so it is all laying in different directions. It will make a small mound once you have put all your chicken on.
You can use the other half of the onion to place on the skewer on the top of the chicken.
Bake for 50-60 minutes or until internal temperature reaches 165F.
Let meat rest for 10 minutes before carving it.