First, preheat your oven to 350 degrees and spray a muffin pan with non-stick cooking spray.
Next begin mashing bananas in a large mixing bowl. Add in sugar, oil, and 1 large egg and whisk until smooth and combined.
Next, add in the self-rising flour in increments whisking in between until just combined. DO NOT OVER MIX.
Using a medium cookie scoop, scoop out the muffin batter evenly into a 12 cup muffin pan that has been sprayed with non-stick cooking spray.
Next microwave the Nutella in a microwave safe bowl for 15 seconds. This makes it easier to swirl in the batter.
Using a teaspoon add a spoonful of the Nutella to the muffin batter in each cup. Next use a toothpick and swirl the batter using “s” motions back and forth.
Bake in the oven for 15-18 minutes, or until a toothpick comes out clean. Let your muffins cool for 5 minutes in the pan, before transferring to a cooling rack until ready to serve.
Serve warm and enjoy!
Notes
Store leftover muffins in an airtight container at room temperature for up to 4 days. You can also freeze them in a ziplock bag for up to 3 months.