Put in a blender all the liquids and the flour and liquefy for 10-12 seconds.
Let the batter rest for about one hour.
Coat a crepe pan with a thin film of butter and scoop 1 ladle of batter.
Once it cooks for about 30-35 seconds, flip the crepe if you can, or turn it with a plate.
Add a generous scoop of Nutella on one side of the crepe with a few slices of bananas.
Fold half of the crepe to cover the Nutella and the bananas to from a half moon.
Cook for a few more seconds ot until the Nutella softens.
Plate and garnish with powder sugar.