Mix the butter, cocoa, powdered sugar and eggs and beat to a uniform mixture.
Crumble the biscuits into many small pieces and add them to the mixture along with the vanilla and chopped nuts.
Mix everything and put it on baking paper or cellophane, at one end of the sheet.
Then roll it up and twist both ends closed to get a sausage-like shape.
Leave for 2-3 hours in the refrigerator.