Heat the olive oil in a skillet over medium heat, and saute the onion, garlic, and ginger until the onion is soft and translucent, about 5 to 8 minutes. Turn off the heat and stir in the turmeric and cinnamon, just to coat the vegetables in the spice.
Transfer the cooked vegetables and spices to the bowl of your slow cooker, then add in the pumpkin, 2 tablespoons of maple syrup, 2 cups of water, and 2 teaspoons of salt. (Use less salt if you choose to use vegetable broth, instead.)
Use a whisk to combine the soup ingredients, and if the mixture is looking very thick, add 1 more cup of water and stir again. (Remember that you'll be adding at least 1/2 cup more liquid at the end of this recipe, so don't make it too thin at this point.) Place the lid on top, and set the soup to cook for 2 hours on high, or for 4 hours on low.
When the cook time is complete, add in the coconut milk for creaminess. I like to use an immersion blender to completely puree the soup, making it extra smooth and creamy, but that's optional. Taste the soup at this point, and make adjustments as needed. If you added extra water, you'll probably need to add extra salt and possibly another tablespoon or two of maple syrup, to boost the flavor. Keep tasting and adjusting until the soup is flavorful and to your liking. (If you add too much salt, then extra sweetness will balance it out, and vice versa.) You can also add more water, a 1/2 cup at a time, if you want to thin-out the soup texture anymore.
Serve this soup warm, with a extra drizzle of coconut cream on top, and with crunchy pumpkin seeds and dried cranberries, if desired. (That's the way my husband likes it best!)
Leftover soup can be stored in an airtight container for up to 5 days in the fridge. It also makes a delicious pasta sauce the next day!