Separate egg whites from egg yolks. Whisk egg whites with half of sugar into the stiff snow. Then in another bowl, mix the butter with remaining sugar (also vanilla) into a foam. Add egg yolks by one into butter and sugar foam and stir well, then add lukewarm milk and dry corpus ingredients (flour, cocoa, baking powder). Lightly add snow and mix. Bake in a round greased tin (approx 28 cm) at 180°C for 25-30 min. Let it cool.

Grate the chocolate. Whisk mascarpone, whipped cream and vanilla sugar, but beware to not over whip it. Add grated chocolate and stir well.

Mark the cut approx 2 cm out of edges in corpus. Scoop out the inside part of corpus into 2-3 cm depth. Set aside the scooped corpus. Cut lenghtwise bananas into halves and put it into scooped hole. Add filling cream and make a hill. Sprinkle the crumbled remaining corpus (the one which you set aside) over the cream filling.