In a medium bowl, combine granulated sugar, brown sugar, cinnamon, nutmeg, cloves and salt together.
Place half of the chopped apples in a crockpot. Sprinkle with half of the sugar mixture and repeat layers.
Cook in slow cooker on LOW for 6 to 7 hours, or until much of the liquid has cooked out and mixture has thickened and is dark brown. Depending on the apple variety, some apples will break down into a sauce, some may simply get soft.
With an immersion blender, puree the apples in the crockpot until desired smoothness.
With the apples uncovered, continue to cook on LOW for 2 more hours.
Spoon the apple butter into sterile containers. Cool, cover and refrigerate for 2 to 3 weeks or freeze for up to 9 months.
