Preheat the oven to 400ºF. Prick the sweet potatoes all over with a fork. Place on a baking sheet and bake for 50-60 minutes or until tender when pierced with a knife.
When cool enough to handle, halve the sweet potatoes and scoop the flesh into a food processor fitted with the steel blade. Add the butter, cinnamon, chili powder, allspice, and maple syrup. Process until creamy and smooth. Season to taste with salt. Serve warm.