Prepare the whole cranberries by sorting through and discarding any that are soft or spoiled. Rinse cranberries under cold water. Slice any especially large cranberries in half and prick the rest with a toothpick, adding each prepared cranberry to a bowl to keep them sorted. Use a citrus zester to zest the orange peel, add zest to the bowl of prepared cranberries.

Set a heavy bottomed pot over medium high heat. In a liquid measuring glass, add juice from the orange. Add enough water to the measuring glass to bring the amount of orange juice up to 1/2 cup (118ml). Measure out 1 cup of cranberry juice (you should have 1 1/2 cups (355ml) of liquid in total). Bring sugar and liquid to a boil.

Once sugar and liquid mixture has boiled for several minutes, turn off the heat and add in the prepared cranberries and orange zest. Stir to coat the cranberries and immediately cover with a lid to trap the heat.

Allow cranberries to soak in syrup for at least 3 hours and preferably overnight for best results. 

Store candied cranberries in their syrup in a glass jar with a lid in the refrigerator (they will keep for one month).