Preheat the oven to 180°C and line a baking tray with parchment paper.
In a bowl, mash the bananas with a fork.
Add the oats, vanilla and cocoa powder, then mix well. Add more oats, if the mixture is not soft.
Let the mixture rest for a few minutes, then add the raspberries and mix again.
Using your hands, make about 10 equal-sized balls, then press them between your palms. Place these on the prepared baking tray.
Bake in the oven for approx. 20 minutes until golden.
Let them cool on a wire rack, then serve.