Peel the banana and put in a longitudinal dish.
Beat cottage cheese, sugar, vanilla and butter in a blender until smooth. Then put the curd on a banana.
Prepare the icing by mixing milk, cocoa, sugar and sour cream. Simmer for about 5 minutes until thick. Allow to cool slightly.
Pour the banana under the coat with icing and sprinkle with chopped nuts. Let stand in the refrigerator for 1 hour.