Put cranberries, sugar, and orange juice in a sauce pan. Stir and cook over medium heat for 10-15 minutes until most of the cranberries have burst.
In a small bowl, mix together the cold water and cornstarch. Add the mixture to the cranberry sauce while stirring. Stir and cook for 20-30 seconds, until thickened.
Remove from heat, cool, and store in the fridge in an airtight container.