Bring the water and granular monk fruit or allulose sweetener to a boil in a saucepan over medium-high heat, stirring until fully dissolved. You should see clear bubbles across the surface within 1–2 minutes.

Add the fresh cranberries, ground cinnamon, and salt to the boiling liquid. Stir to coat the berries so they start popping evenly.

Simmer for 10–12 minutes, keeping the mixture at a steady gentle boil until the berries burst and the sauce thickens. Look for a glossy, spoon-coating consistency and a mix of whole and popped berries.

Remove the saucepan from the heat and stir in the orange zest. The sauce should look brighter in color as the zest disperses.

Taste the sauce and add more sweetener if needed. The flavor should balance tart cranberries with a sugar-free sweetness level you prefer.

Cool the cranberry sauce, then chill before serving. It will thicken further in the refrigerator for a spoonable texture.