Mix biscuit crumb, sugar, butter and cinnamon in a bowl.
Press into the bottom of a 20cm cake tin (any shape is fine).
Bake at 180 degrees C for 10-15 minutes, until browned.
Allow to cool before breaking into suitable sized chunks for adding to your ice cream.
Place in an airtight container and put in the fridge for at least 20 minutes before adding to your ice cream.