Grease the springform pan and dust with flour. Preheat oven (electric cooker: 180 °C/circulating air: 160 °C/gas: see manufacturer). Peel bananas, cut them into small pieces and crush them finely with a fork in a large bowl.
Mix cinnamon, sugar, vanilla sugar, oil and 1 pinch of salt with the whisks of the mixer. Mix flour and baking powder, alternately stir into the banana-oil-mix with soy drink. Roughly chop the cookies, fold them together with the nuts into the dough.
Fill the dough into the springform pan and smooth it down with a dough scraper or wooden spoon. Bake in a hot oven for about 30 minutes, remove from the oven and let it cool down on a cake rack.
For the topping, mix the soy drink, icing sugar, peanut butter and cinnamon in a saucepan over low heat until smooth (see tip below). Leave to cool slightly. Remove the cake from the edge of the springform pan with a damp knife and place on a plate.
Spread the glaze on the surface of the cake with a dough scraper, except for 2 tablespoons for decoration. Peel and slice the banana and spread it on the cake with the biscuits. Decorate with the rest of the icing.