Grease and line a 9 by 5 inch loaf pan with baking or parchment paper. Preheat oven to 180 C (350 F) standard / 160 C (320 F) fan-forced.
2
In a large mixing bowl, sift flour, baking soda and baking powder. Add sugar and cinnamon and gently stir.
3
Heat the butter in the microwave until just melted, stirring in between 10 second bursts. Remove the butter and set aside to cool slightly.
4
Next, add eggs, vanilla and buttermilk to your cooled butter and whisk gently until combined. Make a well in the middle of your dry ingredients, add the wet ingredients and the mashed banana.
5
Very gently stir until the mixture is just combined – be careful not to over mix.
6
Pour the mixture into your prepared tin. Then dollop over Nutella and gently swirl using a butter knife.
7
Bake for approximately 45-50 minutes** or until a knife inserted into the middle comes out clean. Leave to cool completely on a wire rack.