Preheat oven to 350 F.
In a large mixing bowl, mash bananas with a whisk attachment or a fork until smooth.
Add melted butter and blend together.
Add brown sugar, sugar and vanilla to banana mixture and mix well.
In another bowl, add flour, baking powder and salt and mix together.
Add flour mixture to banana mixture followed by the milk and blend until batter is smooth and well mixed.
Grease a bread pan or line bread pan with parchment paper.
Pour batter into pan.
Spoon nutella along the center of the loaf across the length wise distance of the pan.
Sprinkle with hazelnuts and chopped banana if adding it.
If you like a saltier bake, add a sprinkle of salt on top of loaf before you bake.
Bake for roughly 1 hour and 10 minutes or until nutella center sinks and sides rise up and a toothpick can be inserted into the side bread part and comes out clean.
Remove from oven and allow to cool before slicing and enjoying.