Split the Skin
Look for plantains that are very soft and range from nearly black to all black. Start by splitting the skin along one side with a sharp knife.
Peel away the skin, trying to keep the plantain intact.
Cut a deep slit in the plantain lengthwise, making sure not to cut all the way through.
Spread the Cream
Fill the slit with cream. Colombian cream is thick like British double cream, but with a slight tang. Crème fraîche will work well in its place.
Sprinkle the cream with sugar.
Then top it with ground cinnamon.