Boil the fruit, then remove the peel for fruitier flavor.
In a medium saucepan, cover the fruit with water. Bring to a boil over high heat, then reduce heat to medium-high, simmer the fruit for 10 minutes, and drain. Repeat the process until a paring knife easily pierces the peels, up to 2 more times.
Add 1 1/2 cups sugar and 1 cup water to the pan. Bring to a boil, stirring until the sugar dissolves. Scoop out the fruit and slice the peel into 1/8-inch-wide strips. Add the peel to the syrup; reduce heat to low. Simmer until small, fast bubbles appear, about 45 minutes.
Line a baking sheet with parchment paper; set a wire rack inside the pan. Using a slotted spoon, transfer the peel to the rack to drain, spacing the strips apart. Let cool 10 minutes. (Reserve the syrup for another use.)
Pour the remaining 1 cup sugar on a plate. Roll the peels in the sugar to coat; transfer to the rack. Let stand until dry, about 5 hours. Store in an airtight container in a cool, dry place for up to a month.