This Slow Cooker Apple Butter skips the sugar entirely - it's sweetened with a tiny bit of apple cider! No peeling required, and the slow cooker does most of the work.
Core and slice apples. Peel if desired or using a potato masher later; I never bother.
Combine apples, cider, and spices in a 4-quart slow cooker. It will be very full. Cover and cook on high for 5 hours (or low for 10).
Remove lid. Blend mixture with an immersion blender until smooth. A potato masher works, but the result will be chunky. If using a standard blender, cool some before blending.
Do not replace cover. Leave lid off, and cover with a mesh splatter guard. Cook on high for another 2 hours, until mixture has thickened. Stir after an hour if you're concerned about your apple butter burning. You can also leave the lid on but ajar; cover the opening with a towel you don't mind getting messy. You may need to cook the apple butter for longer.
Stir apple butter, then scoop into jars. Store in the refrigerator for up to 2 weeks.
Notes
Use soft apples that will cook down, like Fuji, Cortland, or McIntosh, rather than baking apples. If your apples are tart out of hand, your apple butter may be tart; you can add more cider to balance it, but you will need to cook the apple butter longer.If your apple butter is too sweet, add a teaspoon of lemon juice or orange juice to taste.Use fresh spices. I always grate nutmeg myself, rather than using ground nutmeg.If for some reason your apple butter isn't thick enough, simmer it on the stove for a few minutes to cook out some moisture, or enjoy it as super-delicious applesauce.You can use a 6-quart slow cooker, but may be faster, especially for the uncovered/thickening stage. This recipe was adapted from the Kitchn and Detoxinista.