Preheat the oven to 180C/350F/Gas 4 Line a large baking sheet with baking parchment
Whizz all the ingredients together in a food processor until you get a ball of dough.
Wrap in clingfilm and pop in the fridge for an hour to firm up.
Roll out very thinly to about 2mm/1/8th inch on a floured surface and cut into large rounds. To give mine a real shortbread look I then cut each circle into quarters, or farls as they are traditionally called and pricked them a little with a fork.
Lift all the pieces on to your baking tray (you will have to do these in batches or use a couple of trays) and bake for 10 minutes, or until just golden.
Let them cool on a wire rack - if you can!