Preheat oven 350°F. Grease loaf pan and set aside.
Whisk together flour, baking powder, baking salt and salt. Set aside.
In the bowl of a stand mixer with the paddle attachment, combined brown sugar and melted butter. Add eggs and vanilla. Mix until well incorporated.
Add in banana puree. Mix until thoroughly distributed. *The batter may look curdled.
Add dry flour mixture in two additions, alternating with wet mixture. Begin and finish with the dry. Mix until just combined, until there are no longer any dry streaks of flour. Fold in chopped chocolate hazelnut mixture.
Transfer mixture to prepared loft pan, making sure the surface is even and level. If desired, top with chopped chocolate and chocolate hazelnut.
Bake for 50-60 minutes until toothpick inserted in center comes out clean. Rotate pan halfway through baking. If banana bread gets too brown, make a foil tent to cover bread. Let bread cool in pan for 10 minutes before unmolding and cooling to room temperature on rack. Wait until banana bread is at room temperature before slicing with serrated knife.