Yield: 6 slices
1 navel orange, cut into 6 (1/8-inch-thick) slices
1 ¾ cups sugar, divided
1 cup cold water
1. Preheat oven to 250°. Line a rimmed baking sheet with parchment paper, and place a cooling rack on top.
2. Place orange slices in a large cast-iron skillet. Cover oranges with cold water. Bring to a simmer over medium heat. Simmer for 6 minutes, without stirring; drain.
3. Return oranges to skillet. Sprinkle with 1 cup sugar. Pour 1 cup cold water over sugar, stirring to combine. Simmer over medium-low heat for 15 minutes. Carefully remove orange slices from sugar water. Arrange in a single layer on prepared cooling rack.
4. Bake for 30 minutes. Remove from oven.
5. Place remaining ¾ cup sugar in a shallow dish. Dredge orange slices in sugar, turning to coat both sides. Return to cooling rack. Let slices dry for at least 2 hours.