Add all the ingredients in a crock pot and stir to combine. Cook on high for about 2 hours or until cranberries are softened.
Remove the cinnamon stick, set aside.
In 2-3 separate batches, run the mixture thru a food processor for a minute or two.
Pour the pureed cranberry thru a mesh sieve. Press with spatula or spoon to force puree through. Discard seeds/solids.
Pour the pureed cranberry and cinnamon stick back into the crock pot.
Cook on high with the lid ajar. Cook for about 2 hours or until thickened, stirring occasionally. Try to avoid forming a "skin" on top. I stirred mixture about every 20 minutes or so.
Pour cranberry butter in jars and store in fridge. Cranberry butter should keep for about a month. Enjoy :)