Rinse the cranberries: Rinse the fresh cranberries under cold water and pat them completely dry with a clean towel. Set them in a heatproof bowl large enough to hold the syrup later.
Make the sugar syrup: In a small saucepan, combine 1 cup sugar and 1 cup water over medium heat. Stir occasionally until the sugar fully dissolves and the syrup looks clear, about 3 minutes.
Pour syrup over cranberries: Pour the hot syrup directly over the cranberries in the bowl. Stir gently once so every berry gets coated.
Refrigerate to soak: Cover the bowl and refrigerate for at least 4 hours, or overnight for best results. The berries will plump slightly and deepen in color as they absorb the syrup.
Drain the cranberries: Lift the cranberries out of the syrup with a slotted spoon, letting the excess liquid drip back into the bowl. Discard the leftover syrup or save it for sweetening drinks.
Roll in sugar: Place the remaining 1 cup of sugar in a shallow bowl. Add the drained cranberries a handful at a time and roll them until evenly coated on all sides.
Dry on a tray: Spread the sugared cranberries in a single layer on a parchment-lined baking sheet. Let them air dry at room temperature for 1 to 2 hours, until the sugar shell looks set and dry to the touch.
Serve or store: Serve the candied cranberries right away as a snack or party garnish, or store them loosely covered for serving later. Keep them at room temperature until ready to eat.