Combine the sugar, water, and fresh cranberries in a small saucepan over medium-high heat. Cook for 8-10 minutes, or until the sugar has dissolved and the cranberries have started to soften.
Remove from the heat.
Mash the cranberries gently with a fork to release their juices.
Cover and set aside to cool for 30 minutes.
Once cool, stain through a fine mesh sieve to remove any chunks of cranberry.