1. Heat oven to 225 degrees. Line a pan with parchment. Cut each pear lengthwise into 1/8- to 1/4- inch-thick slices. Remove seeds and fibrous bits from each slice; arrange on pan, spaced 1/2 to 1 inch apart. Sprinkle with sugar.

2. Transfer to oven; dry until pears become firmer, slightly chewy, and shriveled around edges, 1 1/2 to 2 1/2 hours. Transfer to a wire rack. Store in an airtight container, refrigerated, up to 2 days or frozen, up to 6 weeks.