01 -
Add sliced, peeled apples to a 6-quart slow cooker.
02 -
Sprinkle apples with brown sugar, pumpkin pie spice, and salt.
03 -
Cover and cook on low for 8-10 hours, stirring occasionally, until apples are very soft and dark brown.
04 -
Use an immersion blender (or transfer contents in batches to a blender) to puree until smooth.
05 -
Stir in vanilla extract and maple syrup if desired, and cook uncovered on low for 1-2 more hours, until thickened to your liking.
06 -
Let apple butter cool thoroughly and store in airtight jars in the fridge or freeze.