- With the rack in the middle position, preheat the oven to 75°C (170°F). Line two baking sheets with parchment paper and oil lightly.
- In a bowl, dissolve the sugar in the lime juice and water. Set aside.
- Using a mandolin, slice the apples into 2 to 3 mm (1/16 inch) thick circles. Place the slices in the lime juice mixture.
- Drain, then arrange the apple slices on the baking sheets so they don’t touch. Sprinkle with fleur de sel and, optionally, curry powder.
- Bake until the apples are dried, about 4 hours. Let cool and carefully peel them off the parchment.
- Store in an airtight container.
In humid weather, these chips will soften quickly. Return them to the oven as required.