01 - Roast or steam the sweet potato until very soft. Let cool, peel, and cut into chunks.
02 - Combine sweet potato, milk, honey or maple syrup (if using), and vanilla extract in a blender. Blend until completely smooth.
03 - Pour mixture into a saucepan and heat gently over medium-low heat until steaming hot, stirring occasionally. Do not boil.
04 - Pour into mugs. Sprinkle with cinnamon or nutmeg if desired. Serve hot.