1
Melt the butter, and let it cool down while getting the other ingredients ready.
2
Whisk eggs, sugar and vanilla sugar for an airy egg snap.
3
Mix flour and baking powder and gently flip in the dough alternately with the butter.
4
Gently turn the mashed bananas into the dough.
5
Pour the dough into a flat (if it gets too high it may well get a little sticky inside) greased form and place the cake at the bottom of the oven.
6
Turn the banana cake out on a baking rack and allow it to cool.
7
When the cake is cooled, melt the chocolate and spread on top of the cake.