Preheat the oven to 350 degrees F. Lightly coat a muffin tin with cooking spray.
In a large bowl, stir together the bananas, coconut palm sugar (or brown sugar), applesauce, egg and vanilla extract.
In a medium bowl, whisk together the flour, baking powder, baking soda, cinnamon, nutmeg and salt.
Stir the flour mixture into the banana mixture until combined. Stir in two-thirds of the blueberries.
Spoon the muffin batter into the prepared muffin cups. Sprinkle the remaining blueberries over top, press very lightly into the batter.
Bake until a toothpick inserted in the center of the muffins comes out clean, 15 to 17 minutes.
Remove the muffins from the pan and allow to cool. Serve.