Fill the insert of your slow cooker with the chopped apples. Cover and cook on low heat for 10 to 12 hours, or until apples are mushy. You can do this overnight.
Remove the apples and purée in a food processor. Return the puréed mixture to the slow cooker. Add the sugar, cinnamon and cloves. Cook, uncovered, on low until the mixture is reduced to the consistency desired- a very smooth apple butter consistency- 4 to 6 hours.
Pour into jars and refrigerate. This will keep for several weeks in the refrigerator.
Notes
For making apple butter, you want to use a variety of apple that breaks down well while cooking. Recommended: Fuji, Golden Delicious, McIntosh, Jonagold, Red Delicious or Gala (or use a combination of any of these).
If you are familiar with traditional canning, you may be able to can this apple butter. I'm not so familiar, so I can't give advice on that.