In a small saucepan, bring 2 cups of sugar and 1.5 cups of water to a simmer over medium heat, stirring until the sugar is dissolved. Remove from the heat.
Place the fresh cranberries in a medium, heatproof bowl and pour the hot liquid on top; let cool to room temperature.
Cover with plastic wrap and refrigerate overnight.
Using a food processor or blender, pulse the remaining 1/2 cup sugar with the seeds scraped from the vanilla bean until superfine. Transfer to a shallow dish.
Strain the cranberries with a slotted spoon, add to the sugar, and roll to coat.
Transfer the sugared berries to a parchment paper lined baking sheet, and let sit for about an hour until set. Store in an airtight container for up to 2 weeks.
