Place apple slices into a 5-or-6 quart slow cooker. Stir in all other ingredients. Cover and cook on high for 4 hours. Uncover, stir & continue cooking for 2-2 1/2 hours more or until apples are very tender and most the liquid has evaporated. Cool mixture at least 1 hour, or cover and refrigerate overnight.Process with an immersion blender or food processor. Ladle apple butter into 1/2 pint freezer containers, leaving 1/2 inch head space. Seal & label. Store 3 weeks in refrigerator or up to a year in the freezer. makes 4 half-pints