First, heat the water with 1 cup of the sugar over medium low heat until the sugar fully dissolves. Let simmer for 2-3 minutes, then turn off heat and pour sugar syrup into a small bowl to cool to room temp.
Once syrup is cooled, line a cookie sheet with parchment paper and lay your drying rack over the covered sheet. Then toss the cranberries with the syrup in a large bowl until all berries are completely coated. Scoop out berries with a slotted spoon and let them all dry on the drying rack for 45 minutes.
Once nearly dry, toss cranberries with the remaining white sugar until coated, and let dry again on the drying rack or in the bowl for 1-2 hours before eating/using as decoration on cakes!