Preheat the oven to 375˚F. Line muffin pan with 10 paper liners.
In a medium bowl, combine the flours, baking soda, baking powder and salt. In a separate bowl, mix together the bananas, sugar, egg and oil with an electric mixture.
Add the wet mixture to the flour mixture, and mix with a spatula until fully combined.
Scoop the batter into the prepared muffin pan. Spoon one teaspoon of Nutella on top of each muffin, and swirl in with a knife.
Bake for 15-17 minutes, or until a toothpick inserted comes out clean.