Preheat the oven to 360°F (180°C). Line the molds of a muffin tin with paper liners.
Mix dry ingredients: flour, baking powder, and salt in a bowl and set aside.1 ⅔ cup all-purpose flour + 1 ½ teaspoon baking powder + ½ teaspoon fine sea salt
Wet ingredients: Peel and mash the bananas. Set them aside. Beat the eggs shortly; add sugar and oil. Beat for 1 minute. Stir in the mashed bananas.4 overripe bananas + 2 large eggs + ⅔ cup granulated sugar + ⅓ cup canola oil
Sieve the flour mixture over the batter and fold in. Don't overmix!
Swirl: Portion out the batter evenly. Add a teaspoon of Nutella on top of each muffin and swirl with a toothpick.12 teaspoons Nutella
Bake for 20 to 23 minutes or until a toothpick inserted in the middle of a muffin comes out clean.
Rest in the tin for about 5 minutes, then transfer to a wire rack to cool.
Notes
Measurements: A digital kitchen scale will give you the most precise measure, ensuring the best bake possible.
Salt: If using table salt, you will only need ¼ teaspoon.