Mix the sugar and cinnamon in a small bowl and sprinkle it over the apple slices.
2 tablespoons sugar, 1 teaspoon ground cinnamon
Bake in the preheated oven until the apple slices are dried and the edges curl up, about 45 minutes or more.
Transfer the apple chips to a wire rack to cool and crisp up. Serve!
Notes
Apple chips can be stored in an airtight container in a cool, dark place like a cupboard or pantry for up to 1 week. They can also be frozen for up to 1 year.
A mandolin works handy for slicing the apples thinly.