Place the chopped apples into a large slow cooker.
Add granulated sugar, brown sugar, salt, cinnamon, nutmeg, and allspice over the apples.
Pour in the apple cider vinegar and water, then stir gently to combine.
Cover and cook on low heat for 10 hours, stirring every 2 hours to ensure even caramelization.
Remove the lid and cook for an additional 30 minutes to thicken the spread.
Use an immersion blender or potato masher to puree the mixture until smooth and glossy.
Spoon the hot apple butter into sterilized jars and seal immediately.
Let jars cool to room temperature, then refrigerate for up to 3 weeks or process in a water bath canner for long-term storage.