Preheat oven to 350°F. Place cupcake liners in muffin tin.
If sweet potato is not already cooked, boil it in a pot of water until soft. Drain, let cool to touch, and mash.
In a medium bowl, add sugar, water, oil, vanilla and sweet potato; blend well.
In a large bowl, mix together flour, baking powder, salt, baking soda, cinnamon and nutmeg.
In a small bowl, whisk together eggs and apple sauce.
Mix sugar mixture into dry ingredients until just combined. Gently stir in eggs, be careful not to over-mix. Fold in chopped pecans.
Pour an even amount into each muffin cup. Bake for 25 minutes or until a toothpick inserted in the center comes out clean.