Prep the citrus. Zest the orange and squeeze the juice.
Dissolve the sugar. In a saucepan over medium heat, combine the orange zest, orange juice, cinnamon, and brown sugar. Stir until the sugar is fully dissolved.
Cook the cranberries. Add the cranberries and bring the mixture to a boil.
Simmer. Reduce the heat and simmer for about 15 minutes, stirring occasionally, until the sauce thickens and the cranberries burst.
Cool and serve. Remove from heat and let cool completely. Serve warm, or refrigerate for at least 3 hours before serving.
Notes
Texture. Mash the cranberries lightly for a chunkier sauce or more thoroughly for a smoother texture.
Thickening. Cranberries naturally thicken as they cook and as the sauce cools. Continue simmering and mash a few berries if needed.
Sweeteners. Brown sugar adds depth, but white sugar can be used if preferred.
Storage. Store cranberry sauce in an airtight container in the refrigerator for up to 2 weeks.