Preheat the oven to 180 degrees Celsius (356 degrees Fahrenheit).
Beat butter and sugar together well.
Beat in the eggs one at a time.
Beat in banana, cinnamon, baking soda, baking powder, vanilla sugar, flour, and milk at low speed.
Fold in the nuts and chocolate.
Distribute the batter in a loaf pan lined with parchment paper, optionally sprinkle a little extra chocolate and nuts on top. Bake for 45 minutes and serve.