Preheat oven to 190C.
Heat nutella in microwave for 10 seconds blast until nutella is runny.
Don't burn it!
Mash bananas and mix in sugar, egg, oil, and vanilla extract.
In a large mixing bowl, whisk together flour, baking soda, baking powder, salt, and peanut butter chips.
Add wet ingredients into dry ingredients.
Mix until just combined but still lumpy.
Fill liners to 3/4 full, then spoon about a teaspoon of nutella on top of each muffin cup.
Using a skewer or back of knife, create swirls.
Bake for about 20 minutes or until skewer inserted comes out clean.
Leave to cool in pan for 5 minutes, then transfer to baking rack to cool completely.