Place all the ingredients in the slow cooker and stir well. Cook covered on high heat for 2 – 3 hours, or until cranberries have burst and are very soft.
Turn off heat and either puree the mixture in a blender or use a stick blender and puree the mixture right in the slow cooker.
Press the butter through a fine mesh strainer to remove the seeds and skin.
Pour the pressed cranberry butter back into the slow cooker and cook on high with the slow cooker lid ajar for another 2 hours, stirring about every 20 – 30 minutes. This will thicken the butter.
Allow the cranberry butter to cool and store in air tight containers in the refrigerator until ready to use. Will keep in the refrigerator for up to one month.
