Add the apples, granulated sugar, brown sugar, cinnamon, cloves, allspice, and apple cider to the bowl of a 5-6 quart slow cooker and mix well.
Turn the slow cooker on low and cook for 10-12 hours. Do not open or stir!
When the apples are done cooking, cool to room temperature, then refrigerate at least 6 hours or overnight.
When the apple butter is completely chilled, blend in a blender or food processor until smooth. Store in an airtight container (like a mason jar) in the refrigerator up to one month.