Cut apples into ⅛-inch thin slices using a mandoline slicer. Soak slices in a mixture of 1 tablespoon lemon juice and 2 cups water for 5 minutes to prevent browning.
4 - apple, 2 cups water, 1 tbsp lemon juice
Pat apple slices dry with paper towels. In a bowl, combine ground cinnamon and granulated sugar, then toss the dry slices with this mixture until lightly coated.
2 tsp ground cinnamon, 2 tbsp granulated sugar
Line a baking sheet with parchment paper. Arrange apple slices in a single layer, leaving about ½ inch gap between each slice to prevent steaming.
Preheat oven to 225°F (107°C). Bake the apple slices for 1 hour, then flip each slice carefully. Continue baking for another 30 to 60 minutes, until the edges are golden and surfaces are dry without moisture beads.
Transfer the baked apple chips to a wire rack and let cool for at least 10 minutes. The chips will crisp further as they cool. Test for doneness by breaking a cooled chip; it should snap cleanly without bending.
