For the top, separate the eggs and rub the yolks well with the oil, until they become creamy, then add water.
Beat the egg whites with a pinch of salt and when they start to harden, add the sugar gradually, until you get a strong and shiny meringue.
Put the yolks over the meringue and mix at the lowest speed.
Mix the flour with cocoa and baking powder and then sift them on top and incorporate with a spatula lightly, with movements from bottom to top. Put the rum essence and mix once more.
Line a cake with a removable ring with baking paper and turn the dough upside down, then bake at 180 degrees for about 40 minutes. Check if it is done with a toothpick.
Then remove the worktop and let it cool.
Leave a 2 cm edge and then cut with a round knife, like a ring, inside the countertop, but be careful not to go down. Then scoop out the worktop and crush it into crumbs and set aside.
Then prepare the cream. Stop 100 ml of sour cream and mix it with mascarpone until it becomes soft and creamy. Mix the rest of the cream for the cream and when it starts to harden, add the powdered sugar until it becomes hard. Then mix the mascarpone with the whipped cream, lightly with a spatula. Put the chocolate and vanilla flakes and incorporate the cream lightly and ready. It is very strong, consistent, no cream hardener is needed.
Cut the bananas lengthwise and place them in the hollow top. Then put all the cream and coat the cake, giving the shape of a dome.
Then sprinkle the crushed top on the whole cake and decorate with candies or cocoa powder. Leave it in the fridge until ready to serve.