In a medium saucepan combine water, orange juice and sugar; bring to a simmer over medium heat until sugar dissolves.
Stir in orange zest and the cinnamon stick.
Add cranberries to the simmering liquid and return to a gentle boil.
Reduce heat to medium-low and simmer, stirring occasionally, until berries begin to pop (about 8–10 minutes).
Use the back of a spoon to gently crush some berries for a mix of whole and sauced texture.
If using vanilla or maple syrup, stir them in during the last 1–2 minutes of cooking.
Taste and adjust sweetness or acidity by adding more sugar or a squeeze of orange juice as needed.
Remove from heat and discard the cinnamon stick.
Let the sauce cool; it will thicken as it chills.
Transfer to a clean jar or container, cover, and refrigerate for at least 1 hour before serving.