01 -
Preheat the oven to 175°C. Line 18 muffin cups with paper liners and set aside.
02 -
In a small bowl, whisk together the flour, baking soda, baking powder, and salt. Set aside.
03 -
In a stand mixer bowl, combine mashed bananas, melted butter, brown sugar, granulated sugar, eggs, and vanilla extract. Beat at medium speed for 3 minutes until well blended.
04 -
Add the dry ingredient mixture to the wet ingredients and mix on low speed just until no flour streaks remain; avoid overmixing.
05 -
Place Nutella in a microwave-safe bowl and warm for approximately 30 seconds until slightly thinned for easier swirling.
06 -
Spoon batter into each muffin cup, filling about three-quarters full. Add approximately one teaspoon of warmed Nutella atop each and swirl gently using a toothpick or knife.
07 -
Bake in the preheated oven for 15 to 18 minutes or until a toothpick inserted into the center comes out clean.
08 -
Allow muffins to cool in the pan for 15 minutes before transferring to a wire rack to cool completely or enjoy warm.