Place your water (or orange juice) and granulated sugar into a medium saucepan. Set the heat to medium-high and stir occasionally until the sugar completely dissolves. Bring the mixture to a gentle boil. If you are using a cinnamon stick, add it now to infuse the syrup with a warm, autumnal aroma.

Rinse your cranberries in a colander and pick out any mushy or brown ones. Add the berries to the boiling sugar water. Lower the heat to medium-low to maintain a steady simmer. As the berries heat up, they will begin to “pop.” This is the sound of the skins bursting, which releases the natural pectin that thickens the sauce. Stir occasionally and let them simmer for 10 to 12 minutes.

Once most of the berries have popped and the liquid has turned a deep red, remove the pan from the heat. If you used a cinnamon stick, take it out now. Stir in the orange zest if you want a bright finish. The sauce will look a bit thin while it is hot, but don’t worry. It thickens significantly as it cools. Transfer the sauce to a glass bowl and let it reach room temperature before refrigerating.