Peel the bananas and mash them using a blender
To a large bowl add the salt, baking powder, baking soda, and mix.
Add the butter and sugar and mix until creamy. Add the chocolate and the bananas and mix. Add one egg, mix, then add the second. Add the vanilla extract and milk.
Add the walnuts, mixing, and slowly add the flour. Continue mixing until you have a thick porridge-like mixture.
Empty the mixture into a cake tin and bake for 1 hour at 180° C. Decorate with whole walnuts as soon as the cake comes out of the oven, if desired.