Mash the banana with a fork.
In a bowl, mix the mashed banana, eggs, and olive oil together.
Sift in almond flour, baking powder, and cocoa powder, then mix well.
Add chopped dark chocolate to the batter and mix.
Pour the batter into an oven pan and spread it evenly.
Bake in a preheated oven at 180°C for 25 minutes.