Place apples in a 3-qt. slow cooker. Combine sugar, cinnamon, cloves and salt; pour over apples and mix well. Cover and cook on high for 1 hour.
Reduce heat to low; cover and cook for 9-11 hours or until thickened and dark brown, stirring occasionally (stir more frequently as it thickens to prevent sticking).
Uncover and cook on low 1 hour longer. If desired, stir with a wire whisk until smooth. Spoon into freezer containers, leaving ½-in. headspace. Cover and refrigerate or freeze.
Recipe by The Thrifty Couple at https://thethriftycouple.com/easy-crockpot-apple-butter-recipe/