1. Preheat and prep:
   Preheat your oven to 350°F (175°C). Line a muffin pan with paper liners or spray with nonstick baking spray.
2. Mix dry ingredients:
   In a medium bowl, whisk together the flour, baking soda, and salt. Set aside.
3. Combine wet ingredients:
   In a large mixing bowl, mash the bananas until smooth. Add sugar, egg, oil, and vanilla. Mix until fully combined.
4. Combine wet and dry:
   Gently fold the dry ingredients into the wet mixture until just combined. Do not overmix; a few lumps are okay.
5. Add the Nutella:
   Fill each muffin cup about ¾ full with the batter. Spoon about 1 teaspoon of Nutella on top of each muffin. Use a toothpick or skewer to gently swirl it into the batter.
6. Bake:
   Bake for 18–22 minutes or until a toothpick inserted into the center comes out clean (except for melted Nutella!).
7. Cool and enjoy:
   Let muffins cool in the pan for 5 minutes, then transfer to a wire rack to cool completely.

These banana Nutella muffins are best served warm, fresh from the oven, but they’re just as delicious the next day.