Prepare the Apples: Start by washing, peeling, and coring your apples. Cut them into quarters or chunks for easier cooking.
Mix the Ingredients: In a large bowl, combine the prepared apples, brown sugar, cinnamon, and nutmeg. Stir until the apples are evenly coated with the sugar and spices.
Transfer to the Slow Cooker: Pour the apple mixture into your slow cooker, spreading it out evenly.
Cook: Cover the slow cooker and set it to low heat. Allow the apples to cook until they are nice and tender, which will take about 6-10 hours. If you're short on time, you can set it to high heat for 2-3 hours.
Blend: Once the apples are tender, use a blender or food processor to puree the mixture until smooth. If you prefer a chunkier texture, blend it to your liking.
Final Cooking: Return the pureed apple butter to the slow cooker and cook uncovered on high for an additional 2-3 hours, stirring occasionally, until the sauce has thickened to your desired consistency.