Rinse the cranberries. Discard any soft or underripe berries and stems.
Place a medium-sized saucepan over medium heat and add the cranberries, 1/2 cup white sugar, orange zest, orange juice, water, and cinnamon stick. Cook, stirring occasionally until the mixture comes to a boil. Continue boiling over medium heat until the berries burst and break down, forming a sauce, about 15-20 minutes.
Taste for sweetness. If it's too tart, add more sugar - a tablespoon at a time - until the sauce tastes sweet enough for you.
Remove from the heat and let cool. Spoon into your serving container to serve or store in an airtight container, refrigerated, for 3-4 days. This cranberry sauce also freezes beautifully, just place the sauce in an airtight container or a Hefty freezer bag and transfer to the freezer. Before servings, move to the fridge to thaw for about 24-48 hours before the big meal.