Cube the butter into small pieces and place them all in a mixing bowl. Add the icing sugar to the butter, and use a fork to completely mix the two.
Add the all purpose flour to the bowl, and using the fork, mix the ingredients until they start to clump together. With your hands continue to gently mix (knead) the dough until it forms a smooth ball.
Roll out the traditional shortbread dough on a lightly floured counter to roughly ¼ " - ½ " thickness.
Cut the shortbread into squares, fingers, or use a cookie cutter to punch out rounds and other varying shapes.
Place the cookies on a parchment lined or lightly greased cookie sheet, and bake at 325F for 15 minutes.
Remove the cookies from the oven, and immediately remove from the hot cookie sheet to cool.
Garnish these classic shortbread cookies to your heart's content and enjoy!