Combine sugar, ruby port or red wine, orange juice, cinnamon stick, and salt in a saucepan, then set it over medium-high heat until boiling. You should see active bubbling across the surface as the sugar dissolves.

Add fresh cranberries to the boiling mixture and simmer for 10-12 minutes, stirring occasionally, until the berries burst and the sauce thickens. The sauce should look glossy and slightly jammy with visible berry skins bursting open.

Remove the saucepan from the heat and stir in Grand Marnier or orange liqueur and orange zest. The color should deepen and the surface should look shiny.

Discard the cinnamon stick. Make sure no pieces remain in the sauce before cooling.

Cool the sauce to room temperature, then chill before serving. The texture will thicken further as it cools.