Put biscuits into a zip lock bag and finely crush them with a rolling pin (or mortar and pestle). Set crushed biscuits aside.

Using a mixer, beat together egg and sugar until smooth, about 1 minute. Add butter, vanilla and cocoa powder. Beat until smooth and creamy.

Add crushed biscuits and almonds; mix well.

Lay out a sheet of cling film wrap on a dry surface. Spoon the biscuit mixture into a line, about 2 inch thick.

Roll the cling film around the biscuit mixture and form into a log shape. Make sure the cling film is firmly wrapped around the biscuit mixture.

Refrigerate for 10 hours. When they are ready, unwrap the cling film and slice the rolls into 1/2 inch slices. Store them covered in the fridge.