Preheat the oven to 400°. Poke a few holes in each sweet potato using a sharp knife. Place the sweet potatoes directly on the oven rack and bake until very soft, about 45 minutes. Alternatively, you can microwave them for about 8 minutes, checking every minute or so after the first 5 minutes.
When the sweet potatoes are done baking, slice them open to allow the steam to escape. Allow them to sit for a few minutes to cool.
Lower the oven temperature to 375°. When the sweet potatoes are cool enough to handle, scoop out the insides and place them into food processor bowl. Add the coconut milk, maple syrup, vanilla, cornstarch, cinnamon, ginger, cardamom, nutmeg, cloves, and salt. Process until smooth, stopping to scrape the bowl as needed. Pour the batter into the pie crust and smooth out the top with a rubber scraper.
Bake for about 40 minutes, or until set. Remove the pie from oven and allow it to cool completely before slicing.
This amount is for a just slightly sweet pie. If you like a sweeter pie, add a bit more maple syrup. Taste test the mixture until you're happy with the flavor.
* I've updated the spice amounts since originally posting the recipe, after getting quite a few comments that it was too spicy. But feel free to taste test the sweet potato mixture and adjust them based on your taste.