Cut off both ends of the unpeeled bananas. Steam in a sieve insert over steam in a closed pot for 5 minutes.
In the meantime, mix the flour, sugar and cinnamon well in a saucepan and gradually stir in the coconut milk. Bring everything to a boil and reduce until creamy, stirring again and again. Finally, let the butter melt in the sauce. Carefully peel the bananas and pour the sauce over them.
Variants: Stir ½ cup of natural yoghurt into the sauce or fry the peeled bananas in a little butter.