First, pour boiling water over cranberries and let them sit until they pop. Drain immediately. (this breaking down of the outer skin is called “checking”)
Arrange on baking sheet, sprinkle with granulated sugar and freeze for 2 hours to break down the cell structure.
Arrange in a single layer on mesh sheets in drying trays. Place in dehydrator and dry at 140 degrees until dry, about 10-16 hours. The cranberries may still be sticky, and should definitely be chewy, but with no pockets of moisture. Store airtight at room temp or in freezer.