Add the olive oil to a large pot over medium heat, and saute the onion and apple until softened, about 5 minutes. Add in the garlic, cinnamon, and cayenne, and stir for 1 minute.
Add in the butternut squash, water, and salt, and stir to combine. Bring the water to a boil, then lower the heat and cover the pot to let the soup simmer until the squash is fork tender, about 25 minutes.
When the squash is tender, add in the almond milk and maple syrup, and puree the soup with an immersion blender. (Alternatively, you can transfer the soup to a blender and carefully blend it, with your blender vent lightly covered with a thin towel so the lid doesn't blow off-- be careful not to burn yourself!)
Taste the soup and adjust any seasoning to taste, adding freshly ground black pepper, along with more salt or maple syrup, as desired. Serve warm.
Leftover soup can be stored in an airtight container in the fridge for up to a week, or in the freezer for up to 3 months.