
Place cored and sliced apples (not peeled) into a large slow cooker or crock-pot.
Add apple cider vinegar (or water) and spices. Stir all ingredients together, cover, and let it cook for 5-6 hours on low.
Once the apples are very soft, turn the slow cooker off and use an immersion blender to puree the apples until smooth.
Turn the slow cooker on high and heat the apple butter for 1-2 hours uncovered to help it thicken and caramelize.
Cool for 30 minutes before transferring into airtight containers for storage.
The apple butter will keep in the fridge for up to 3 weeks or in the freezer for up to a year.