How to make
Hydrate the gelatin according to the instructions on the packet. Meanwhile, heat the cream with the sugar over medium to low heat. Once steam starts to come out of it and it is about to boil (but it should not boil), remove it from the heat.
Mash two of the bananas along with the yoghurt and it is best to use very ripe and soft ones for the cream, which you can also easily mash with a fork, but you will still get a smoother cream if you blend them. The third banana, which we will use for decoration does not need to be soft and too ripe.
Dissolve the already hydrated gelatin in the hot cream - and since we have removed it from the heat minutes before it boiled, it will not be boiling, because in such a situation a high temperature would neutralize the action of the gelatin.
Once the gelatin is dissolved, mix very well and pour the banana-milk mixture and vanilla and mix again, until a homogeneous mixture is obtained.
In a cake tin with a detachable bottom (22-23 cm in diameter) arrange a layer of biscuits, maybe two, depending on how thin they are. Pour the cream over them and don't worry if some of them rise, you can even add more biscuits on top. The idea is for then to sit carelessly all over the cream when it thickens.
Allow it to cool and refrigerate it for 4 hours. When you see that the cake has hardened, start making a cream-couverture, which will taste like caramel, perfectly matching the taste of the banana.
Caramelize the sugar with a pinch of salt over medium heat, until it aquires a light brown color, then pour the warm cream and half the milk plus the condensed milk. Stir to homogenize and so that the caramel does not become lumpy.
Dissolve the starch in the remaining milk and pour it in a thin stream, by stirring at all times, until the cream thickens. Then add the butter and once it melts pour it over the cake. Again, allow it to cool and set it aside for at least 1 hour.
Cut the third banana into circles and drizzle it generously with lemon juice, so that it does not darken. Arrange the circles on the cake and if it is already firm enough, unclip the form and stick small biscuits on the edges or in the absence of such - crush ordinary biscuits and stick them. If you are not one of those families whose desserts go quickly, I recommend adding crushed nuts, as the biscuits may soften after a day or two and not be as crunchy as we would like.
Sprinkle with grated dark chocolate if you like.
Enjoy!
