With a fine needle pierce around your oranges several times. Making sure to insert the need right through the skin or the oranges. This allows the candying syrup to penetrate the oranges. Do not use a skewer!
Place oranges in a large pot (which has a lid) and cover with water. Bring water to a simmer and cook for an hour. This will remove some of the bitterness from the pith of the oranges.
Drain oranges in a colander and set aside.
In the same pot add your sugar, water and corn syrup. Heat until sugar has dissolved and then increase heat until the syrup boils. Reduce heat and place your oranges back in the pot. Place lid on your pot, but do not fit it tightly, leave it slightly off centre, as you want some of the steam to escape. Gently simmer for an hour, make sure it is a very gentle simmer.
Remove pot from the heat and place lid firmly on top of your pot.
The same time next day, place pot back on stove. Place lid slightly off centre again and bring oranges and syrup to a gentle simmer again. This time simmer for 30 minutes.
Once you have done this, remove pot from the heat again, replace lid and leave until the same time the next day.
You repeat this process for eight (8) days. You may need to add a little water if your syrup is reducing too much.
Once you have simmered for your final day. Cool oranges completely and store in a container in your fridge. They will keep for up to six (6) months.
Don’t discard the syrup either as this takes on a deep orange flavour. This then can be used for cordial or many other purposes.