Preheat the oven to 175°C convection.
Mash the bananas in a bowl.
Add the eggs, cocoa powder, vanilla extract, and baking powder to the mashed bananas.
Melt the butter and let it cool briefly. Then add it to the mixture.
Mix everything well until a batter forms.
Stir in the hazelnut butter and a pinch of salt.
Optionally, you can now add some maple syrup if you like it sweeter.
Finally, fold the chocolate chunks into the batter.