Add vegetable stock, garlic, carrot, apple, butternut squash, sage, onion, salt, pepper, cayenne, cinnamon, and nutmeg to a small (4 quart) slow cooker or large (6 quart) slow cooker.
Toss to combine.
Cook for 6-8 hours on low, or 3-4 hours on high, or until the squash is completely tender and mashes easily with a fork.
Remove and discard the sage.
Stir in the coconut milk.
Use an immersion blender to purée the soup until the smooth. (Or you can transfer the soup in two batches into a traditional blender, and purée until smooth), being very careful when working with the hot liquid.
Taste, and season with additional salt, pepper, and cayenne, if needed.
Serve warm, with optional garnishes, if desired. Enjoy!