Prepare the Cranberries: Rinse the cranberries under running water and discard any soft or mushy ones. Set aside.
Combine Ingredients in a Saucepan: In a medium saucepan, combine the water and sugar. Stir over medium heat until the sugar dissolves completely.
Add Cranberries and Flavorings: Add the cranberries to the saucepan. If using, add the orange zest, orange juice, and cinnamon at this point. Stir to combine.
Simmer: Bring the mixture to a gentle boil, then reduce the heat to medium-low. Let the cranberries simmer, stirring occasionally, for about 10-15 minutes. The cranberries will burst and the mixture will thicken.
Adjust Consistency and Flavor: Taste the cranberry sauce. If you prefer it sweeter, you can add more sugar to taste. If it's too tart, add a bit more sugar. For extra flavor, adjust by adding more orange zest, juice, or cinnamon, based on your preference.
Cool and Serve: Once the sauce has reached your desired consistency and flavor, remove it from the heat. The sauce will continue to thicken as it cools. Transfer it to a bowl or airtight container and let it cool to room temperature. Then refrigerate until ready to serve.
Optional Step: If you prefer a smoother sauce, you can use an immersion blender or regular blender to puree the cranberry sauce once it has cooled slightly. Be cautious when blending hot liquids.
Serve: Cranberry sauce can be served chilled or at room temperature alongside your favorite dishes, particularly with roasted meats like turkey, chicken, or as a spread on sandwiches.