For the Nutella banana cream, mix 3-4 bananas with yogurt.
Whip the curd and add the banana-yogurt mixture. Add lemon juice and rum, as well as sugar and vanilla sugar and mix well. Put the mixture in the refrigerator for about 5 minutes.
Meanwhile, whip the whipped cream and stir into the mixture. Add a little sugar or rum to taste.
Divide the mixture into two containers. To one half of the mass add Nutella to taste.
Carefully spread 6 wafer shells with a little Nutella and fill alternately with the light and dark mass. Possibly add a layer of sliced bananas in between. Leave some mixture for decoration. Cover the finished bowls with plastic wrap and place in the refrigerator.
Before serving, decorate the bowls with the remaining mixture, bananas and chocolate flakes. Since the shells are now soft, it is best to put them in a second waffle bowl and serve the Nutella banana cream.