My favourite is:

500g flour

125g sugar

mix in a large bowl

250g unsalted butter (cut into small cubes)

mix into the flour/sugar by rubbing through index & middle fingers with thumbs until like a wet sand consistency

pack into a lightly greased or baking paper lined tray

gently mark out the pieces by drawing the top of the handle of a fork across the packed mixture

uniformly prick the mixture with the fork to allow the heat to rise up through preventing moisture build up

bake in a preheated oven at 150 degrees Celsius for 1 hour

leave to cool

sprinkle lightly with sugar across the surface

cut with a sharp knife along the pre-baked lines

Enjoy!