Preheat the oven to 375°F. Line two muffin pans with paper liner and set aside.
In a large bowl, mix together the bananas, butter, sugar and eggs until fully combined.
Add in the flour, cinnamon, baking soda, baking powder and salt.
Fold in the oats and blueberries until just combined.
Fill the muffin cups around 2/3 of the way up. Sprinkle with the sparkling sugar.
Bake in the preheated oven for 18 minutes, or until a toothpick inserted in the centre comes out clean.