Peel the bananas and slice them fairly thinly - about ¼ inch slices. Try and get them all similar sizes otherwise some will be ready and others will need longer. This is not so much of an issue in the dehdyrator but it does mean that the thinner bananas will become much harder than the thicker bananas. To avoid this problem, I use my Banana Slicer. All you do is put the peeled banana underneath it and push down. The slices of bananas are all cut at the same time and they are all the same width. You can get really fast at this very quickly using this tool.

Lay out all of your banana slices on your dehydrator tray or non stick oven mat. It doesn’t matter if the slices touch each other as they are going to shrink in size.
Sprinkle the slices with cinnamon if you are using it. You could also use carob or cacao powder instead of the cinnamon.

Dehydrate for about 24 hours at 115F/45C until the bananas are at your desired hardness. The harder they become, the longer they will last.

You can also bake them in the oven at 225F/105 C for 2-3 hours. But check on them every half an hour to see how well they are cooking as you might need to remove them earlier than planned.

You can store the banana chips in a sealed container at room temperature for up to 3 months depending on how much moisture was removed during the baking.

Another variation is to slice the bananas lengthways which makes great banana slices for cinnamon rolls.