Melt the chocolate with the butter in a double boiler.
Chop the walnuts in the mixer.
Work the egg and sugar combo with a whisk until a swollen and frothy mixture is obtained.
In a bowl, with the help of a fork, mash the two very ripe bananas, reducing them to a puree.
Add the banana puree, the chocolate with the butter, the chopped walnuts, and the flour with the baking powder to the egg and sugar mixture.
Transfer what has been obtained into a buttered and floured pan. Bake in a hot oven at 180 ° C for 30-35 minutes.
Do the toothpick test.
And when it’s cooled completely, decorate to your pleasure.
I decorate it with finely chopped walnuts and caramelized chopped bananas.