Cook cranberries in water over medium heat until cranberries burst. Add butter, sugar, cinnamon, and ginger; stir. Bring to a boil, stirring occasionally. The longer it boils, the thicker it will be. 2-3 minutes for a loose sauce, 5 minutes for a more set sauce. Let simmer for 2-3 minutes. Let cool. Can be served warm or cold. ***The longer it boils, and the colder you serve it, the more it will set up. Increase the sugar to your tastes, I like mine tart. Add a splash of lemon juice if you make it too sweet.