First of all, turn on the oven and set the temperature to 190°C.
Then stir together 100g butter and 50g caster sugar in a bowl until you have a smooth, light coloured mixture.
Next, add 150g plain flour and a pinch of salt. Stir thoroughly again.
Once you've done that, roll out the mixture to a thickness of 1cm and cut into squares.
Finally, put a bit more sugar on top of the biscuits and bake in the oven for 15-20 minutes.
https://339efcb25eb75e967b0d-ff8eeadd950d51fd1fc939dca75b3973.ssl.cf1.rackcdn.com/assets_green.swf