How to cook
This cake is suitable for just about any occasion, including unexpected guests. Leave the butter and liquid chocolate at room temperature.
To make the cream, put the liquid chocolate and sour cream in a bowl, stir with a spatula until completely mixed. Don't beat with a mixer because the cream will liquefy and it will be more difficult for it to harden later.
Cut the bananas into thin round slices or pieces. Put 1 tsp of the cream in a large platter and smear it along the bottom, place the first cake layer. This way, the cake layer will stick to the platter and not move while you're forming the rest of the cake.
Divide up the cream (eyeball it) so that you have enough for smearing all 3 cake layers. Smear the 1st cake layer with the cream, put a little of the sliced bananas and place the 2nd layer on top, smear with cream again and put bananas, place the final layer and smear on the remaining cream, while also smearing the sides of the cake. Leave the cake in the fridge to harden.
In the meantime, make the chocolate ganache, to complete the cake. Heat the confectionery cream on the stove, remove it before it comes to a boil and add the crumbled chocolate and the butter. Leave it as is for about 1 min., then stir until you get a smooth homogeneous chocolate mixture.
Leave it aside for a few min. to cool and then pour it over the cake. Using a knife, distribute the ganache along the entire cake and return to the fridge. Chop several pieces of bananas and pour lemon juice over them, so they don't brown. Arrange them on the cake and finish off the decoration with a few mint leaves.
You can decorate as desired. Mine was a simple one but the quickest I could think of. It's best to leave the cake for several hours in the fridge for the cream to harden well - you can also use gelatin or cream stabilizer. In my case, we just couldn't wait for it to harden much and when we cut it, the cream was still runny but we still ate it in no time. :)