chop biscuits in TM bowl 3s speed 3-4 (depending on how chopped up you like the biscuits) and remove.
place butter, sugar and cocoa into TM bowl and melt for 2 mins at 60 degrees speed 4
add remaining ingredients and mix for 30s speed 1.5
press mixture into a lined baking tray and chill for an hour
melt chocolate and butter for topping in TM bowl for 2 minutes at 50 degrees speed 3
spread over slice and allow to set in the fridge for 20 minutes