Homemade apple butter made in the slow cooker could not be easier! Simply mix up your apples, sugar, and spices and let it cook down all day (or overnight), puree it, and enjoy.
Place apples in slow cooker. In a medium bowl, whisk together the sugars, cinnamon, nutmeg, cloves and salt. Sprinkle over the apples and stir gently to combine. Cook on low for 10 hours.
Stir in vanilla extract, breaking up any large chunks of apples that remain. Cover and cook for an additional 2 hours.
Remove the lid and use an immersion blender to puree the apple butter until completely smooth or to desired consistency. (Alternately, you could puree in batches in a food processor or regular blender.) If you want the apple butter thicker, you can continue to cook it on low with the lid of the slow cooker slightly ajar so that steam can escape.
Allow the mixture to cool, then spoon into jars and store in the refrigerator for up to 1 month, or freeze for up to 1 year.