In a large bowl, mix the walnuts, pecans, raisins, butter, and cinnamon. I use a wooden spoon for this bit of dirty work.

Using a small paring knife, cut out the apple cores, being sure to leave some apple at the bottom. Fill the apples with the nut mixture (pack it in there tight!), and place them in your slow cooker.

Pour the apple cider into the slow cooker. Set the slow cooker on low, and cook for 6−8 hours. Enjoy the smell of autumn that wafts through your kitchen!