01 - Preheat the oven to 225°F. Line two baking sheets with parchment paper or silicone mats.
02 - Wash and core the apples. Using a mandoline or sharp knife, slice apples crosswise into thin rings approximately 1/8 inch thick.
03 - Place apple slices in a large bowl and toss with lemon juice to prevent browning.
04 - In a small bowl, combine ground cinnamon, nutmeg, allspice, and granulated sugar if using. Sprinkle mixture evenly over both sides of the apple slices.
05 - Spread the apple slices in a single layer on the prepared baking sheets, ensuring slices do not overlap.
06 - Bake for 1 hour, then carefully flip each slice. Continue baking for an additional 45 to 60 minutes, or until the apples are dry and crisp.
07 - Remove the baking sheets from the oven and allow the apple chips to cool completely; they will crisp further as they cool.
08 - Store the cooled apple chips in an airtight container for up to one week.