In a medium pot, bring the sugar and water to a boil over high heat. Stir and reduce heat to medium-high. Boil until the temperature reaches between 300 ̊ and 310 ̊ (the hard-crack stage).
To test for the right temperature, let a drop fall onto a plate. If it stands up stiffly, the sugar mixture is ready.
Line the apples on a parchment-lined baking sheet and insert a wooden skewer about half-way through the stem-side of the core.
When the sugar reaches temperature, immediately remove the pot from the heat and stir in the cinnamon quickly. If the sugar has time to sit, it will begin to harden on the surface.
Dip the apples into the sugar, twirling them around until they are completely coated and then transfer them back to the baking sheet.
Sprinkle the lemon zest and confetti over the apples while they are still warm and sticky. Cool completely before serving.