Preheat the oven at 175 degrees Celsius.
Mash the bananas in a bowl with a fork.
Whip the sugar and the eggs fluffy in another bowl with an electrical mixer.
Melt the butter in a casserole and pour it in the egg and sugar mixture.
Add the bananas in the bowl with the batter and whip together.
While still whipping add the flour, vanilla sugar, baking powder and the milk in the batter.
Butter a rectangular baking form and add the bread crumbles in the form.
Pour the batter in the form, and put it in the middle of the oven for approx one hour.
Take out the cake and let it cool down before serving it.