Take a medium-sized orange, apple and star fruit (you can use other fruit, too—any citrus, kiwi, bananas). Cut them unpeeled into thin circles—it is best to use a slicer. Take out the seeds. If the fruit is not very sweet, put some powdered sugar on both sides.
Now you should dry the slices till crunchy. You can do it using a gas or an electric oven at 60 °C (140 °F) degrees leaving the oven door open, or in an electric fruit dryer. If you use the oven, do not forget to put parchment paper on the tray to prevent fruit from sticking.