Preheat the oven to 375°F and line or grease your muffin tin. In a large mixing bowl, use a fork to mash the bananas.
3 large overripe bananas
Add the oil and light brown sugar and use the fork to combine.
⅓ cup oil, ¾ cup light brown sugar
Next, add the egg and vanilla extract and use the fork again to mix.
1 large egg, 1 teaspoon vanilla extract
Add flour, baking soda, salt, and cinnamon and mix with the fork one last time until you're left with a thick batter. You will likely have some chunks of banana, but make sure there are no lumps of flour.
1 ½ cups all-purpose flour, 1 teaspoon baking soda, ½ teaspoon salt, ¼ teaspoon cinnamon
Add 1 heaping tablespoon of batter to each muffin cup.
Then, add a tablespoon of Nutella on top.
¾ cup Nutella
Top the Nutella with more banana muffin batter, so that the Nutella is sandwiched in between batter. The muffin cups should be filled about 3/4 of the way.
Bake on the top rack for 18 minutes and allow to cool before digging in. Enjoy!