Firm, underripe pears
Very thinly slice pears lengthwise with a mandoline or chef's knife and place in a single layer on parchment-lined baking sheets. Bake in a preheated 225 degrees oven 1 1/2 hours. Flip slices and continue baking until darkened slightly and edges have curled (they should still be pliable), 1 to 1 1/2 hours. Transfer to a wire rack and let stand until cool and crisp. Store at room temperature in an airtight container up to 1 week.
CINNAMON-SPICED
Liberally sprinkle tops of slices with cinnamon sugar. Bake as indicated above.
MAPLE-GLAZED
Generously brush tops of slices with maple syrup. Bake as indicated above