Method
1. Pre-heat oven - 190°C
2. Prepare a clean loaf pan
3. Add salted butter and powdered sugar to a clean stand mixer bowl
4. Mix until creamy - 3 min
5. Add egg and rum to a clean small bowl
6. Mix wet ingredients into batter gradually
7. Add all purpose flour, baking powder and hazelnut flour to a clean medium bowl
8. Mix briefly until combined
9. Transfer dry ingredients to batter
10. Add banana, chocolate chips and walnuts to a clean medium bowl
11. Mix content of medium bowl into batter gently
12. Fill the pan 3/4 full - the cake will rise!
13. Bake until golden brown - 35 min, 190°C
14. Let cool - approx 15 min