Process all the ingredients for the base in a kitchen machine, leaving them a bit chunky.
The mix will first become crumbly and will stick to the sides,but then gradually will become sticky and start to clump together into a kind of dough. It needs to be oily and when you grab some of the dough and roll it in your fingers it must stick together.
Take a square dish and line it with baking paper so that there is an overhang on each side.
Press the brownie mix down into the dish.
Put all the Icing ingredients into the blender or kitchen machine and blend until smooth.
Spread icing over the base and pop it into the freezer for one hour.
Cut into snack-size squares.
Notities
This recipe makes quite a lot so if you have a small food processor just split it up into two batches.