Roughly break the plain biscuits into small pieces
Melt the dark chocolate. Set aside
Whisk softened butter, icing sugar, vanilla essence and liquor until smooth
Add a pinch of salt
Add melted chocolate and mix
Add crushed biscuits, pistachios, and cocoa powder and mix together
Shape into a log with baking paper and wrap. Refrigerate for 4h
Dust with icing sugar before serving
