Chocolate ice-cream sandwiches

Instructions

• Put the amaretti biscuits in a blender or food processor, and whiz until
  they form coarse crumbs.
• Take one of the digestive biscuits and spread a 2.5cm/1in layer of ice
  cream on its non-chocolate side. Sandwich another biscuit on top,
  chocolate side uppermost. Squeeze the biscuits gently together and
  smooth the ice cream around the edges. Repeat with the remaining
  biscuits and ice cream.
• Roll the edges of the biscuit sandwiches in the crushed amaretti biscuits
  to coat them, then place on a tray in the freezer. Freeze for at least
  2 hours before serving.