Combine apple chunks, granulated sugar, brown sugar, cinnamon, nutmeg, cloves, and salt in a 6-quart slow cooker.
Cover and cook on HIGH for 5 hours or on LOW for 8 to 10 hours.
Let cool slightly and transfer to a blender. Blend until smooth.
Note: if apple butter is too thin, return to slow cooker and cook on HIGH for 1 hour uncovered, stirring occasionally. Keep in mind it will thicken some as it cools.
Notes
Good apples to use are Gala, Honeycrisp, and Granny Smith. I use a mixture.