For dried orange slices, first preheat the oven to 100 °C hot air.
Cut the oranges into slices about 1/2-1 cm thick.
Place on a wire rack and put into the oven. It is best to put a tray underneath in case the oranges drip.
Dry in oven for about 3-5 hours (depending on how juicy the oranges are and how the oven works).
Remove dried orange slices and let cool.