Read before you begin: You need fresh orange juice and orange zest. I recommend zesting the orange first, setting the zest aside, then cutting the orange for the juice.
After rinsing the cranberries, set ½ cup cranberries aside for extra texture.
Combine the remaining cranberries, water, orange juice, and brown sugar in a medium saucepan over medium heat. Stir occasionally as the mixture comes to a simmer. Once simmering, reduce heat to low-medium and continue to cook until the liquid has reduced and cranberries have burst, about 15 minutes.
Remove from heat and stir in the reserved cranberries, orange zest, and vanilla extract. The sauce will thicken as it cools.
Serve warm or at room temperature. Cover and store leftovers in the refrigerator for up to 5 days.