Add diced apples, sugar, cinnamon, cloves and salt to a slow cooker. Cover, and cook on high for 1 hour.

Reduce to low heat. Cook stirring occasionally, for 4-6 hours, or until thick and golden brown in colour.

Use a immersion blender in the slow cooker to blend the apple butter until it's smooth -taking care that the hot apple butter doesn't splash you. Store in a mason jar in the refrigerator.