Put potato, carrots, banana and eggs into a blender or food processor. Blend until smooth.
Pour into a bowl, and mix in remaining ingredients until just combined.
Fold in nuts and raisins, if desired.
Line a 12-cup muffin tin with paper liners and evenly pour batter into 9 of the cups.
Bake for 20-25 minutes, or until a toothpick inserted into the center of a muffin comes out clean.
Let the muffins cool completely before eating. Extra muffins can be stored in fridge for up to 5 days or in freezer for up to 3 months. Thaw frozen muffins in fridge for a few hours before eating.