Preheat your oven to 225°F (110°C). Line a baking sheet with parchment paper or lightly spray it with cooking spray.
Wash and dry the apples thoroughly. Using a sharp knife or a mandoline slicer, cut the apples into very thin slices (about 1/8 inch thick). You can leave the skin on for extra texture and nutrition.
In a small bowl, mix together the granulated sugar, ground cinnamon, and a pinch of salt until evenly combined.
Arrange the apple slices in a single layer on the prepared baking sheet. It’s important that they do not overlap to ensure even cooking.
Sprinkle the cinnamon sugar mixture evenly over the apple slices, coating them generously.
Bake in the preheated oven for about 1 to 1.5 hours, turning the apple slices halfway through the baking process to ensure even crisping. Keep an eye on them toward the end; they should be dry and crispy but not burnt.
Once done, remove from the oven and let the apple chips cool completely on the baking sheet. They will continue to crisp up as they cool.
Store the cooled apple chips in an airtight container for up to a week. Enjoy as a healthy snack or a crunchy topping for desserts!