Prepare the oranges by first zesting, peeling, slicing and dicing one orange.
Using a citrus zester, zest one orange over a plate or piece of parchment paper and set aside. Place in a small bowl and cover with plastic wrap, this zest will be added when the sauce is cooled.
Place the zested orange on a small plate and using a serrated knife cut away the orange peel. A plate will catch any of the juice.
Keep the orange on the plate and then using the serrated knife, cut the orange in slices, and then with a pair of kitchen shears or a serrated knife cut the orange slices into small pieces.
Cut the other orange in half, and using a citrus reamer, juice the orange and strain out any seeds or pulp. I usually have about ⅓ cup of orange juice.Optionally, you can add a ⅓ cup of bottled orange juice.
Rinse the cranberries under cold water then place them in a medium-sized saucepan along with the sugar, the orange pieces and any juice, the juice from one orange, and the cinnamon stick.
Turn the heat to medium and stir all the ingredients. Bring to a slight boil then turn the heat to medium-low and continue cooking until the mixture starts to thicken, about 15-20 minutes. Make sure to stir occasionally and you will hear the cranberries pop during cooking.
The sauce is ready once the cranberries have softened and this will continue to thicken up after the sauce cools. Pour the sauce into a small bowl to cool.
Store covered in the refrigerator.
To serve top with the orange zest, or you can stir the orange zest into the cranberry sauce.