Preheat the oven to 400F. Prick the sweet potato a few times with a paring knife or fork. Bake until soft (when a paring knife can cut through with zero resistance), about 1 hour. Set the sweet potato aside until its completely cool.
Peel the sweet potato, discard the skin and mash the flesh in a mixing bowl with a fork. Whisk the olive oil, almond milk, maple syrup or xylitol, and vanilla into the sweet potato. In a separate bowl, whisk together the flour, baking powder, baking soda, five-spice powder and salt. Fold the dry ingredients into the wet ingredients.
Line a 12-cup muffin tin with paper liners and evenly distribute the muffin batter among the cups.
Bake at 400F for 20 to 25 minutes, or until a toothpick comes out clean, brushing the tops with extra maple syrup during the last 5 minutes of baking. Let the muffins cool before serving.