Warm milk in a pot lukewarm. Remove from the heat, crumble yeast into it and dissolve it while stirring. Mix flour, sugar, vanilla sugar and 1 pinch of salt in a large bowl. Add yeast milk and knead in - the dough is very liquid.
Cover and leave to rise in a warm place for about 45 minutes.
For the chocolate sauce, break the chocolate into pieces. Heat the cream. Melt the chocolate in it. Let it cool down.
Melt the butter and let it cool down for about 10 minutes. Separate the eggs. Whisk the egg yolks. Beat the egg whites with the whisks of the mixer until stiff. Add egg yolk and liquid butter to the dough, fold in with a wooden spoon.
Add the egg white in portions.
Preheat a rectangular waffle iron and spread a thin layer of oil on it. Bake approx. 16 golden brown waffles one after the other from 2 tbsp. yeast dough at medium heat, cleaning the waffle iron if necessary.
Peel and slice the bananas. Sprinkle with lemon juice. Dust the waffles with icing sugar and serve with bananas and chocolate sauce.