Before you slice the apples, twist the stem off and wash thoroughly to remove pesticides or wax. Using a mandoline slicer or a very sharp knife, slice apples into ⅛" thin rounds. There is no need to peel the apples unless you want to.
Arrange apple slices in a single layer, onto clean dehydrator trays. Leave plenty of room for air circulation. Sprinkle apple slices with cinnamon and cardamom, if you'd like.
Set the dehydrator's temperature to the fruit/vegetable setting, which is usually 135-degrees F). Set a timer for two hours.
After two hours, start checking the apples periodically, until the desired texture is achieved (either soft and pliable or crispy). Dehydrating times will vary based on how juicy the apples are, the thickness of the slices, and the model of dehydrator being used. However, the longer you dehydrate them the crispier they will become.
Store in air-tight container for up to 6 months.
Video
Notes
See post for oven and air fryer directions.
It's a good idea to use a mandoline to slice the apples so that the apple slices have a consistent thickness. This will allow them to dehydrate at the same rate. Always use the food holder when slicing the apples so that you don't slice your hand accidentally.
One apple makes approximately 20 slices when sliced into ⅛ " thickness.
Thinner slices are much easier to slice with a mandoline than thicker ones.