Peel the bananas and chop each one into fairly thin rounds.

Place the bananas in a Ziploc bag or sealed container and leave in the freezer until completely frozen.

When frozen, place the bananas in a food processor with the cocoa powder, peanut butter and milk. Process until all the ingredients are completely blended - you might have to scrape the inside of the bowl down a few times.

Taste and add more cocoa powder or peanut butter if you think it needs it. If the mixture is too thick, add more milk.