To prepare for this, slice the bananas and freeze on a parchment covered baking sheet for at least 25 minutes.
Put the frozen sliced bananas and cocoa powder in a food processor (a blender can also be used) and turn on.
Blend together until the mixture looks like soft serve ice cream (1-2 minutes).
Notes
The provided nutrition information does not include any added sodium from seasoning to taste, any optional ingredients, and it does not take brands into account. Feel free to calculate it yourself using this calculator or by adding the recipe to Yummly.