Preheat oven to 375 degrees.
In a medium mixing bowl, combine butter and sugar. Mix well, but do not cream.
Add the flour and combine with butter and sugar until it just comes together into a smooth dough. Dough will be quite stiff. You can initially cut the butter into the flour with a pastry blender, but then use your hands finish bringing the dough together.
Shape the dough as desired, prick all over with a fork and score with a dough scraper or knife as necessary.
Bake for 10 to 20 minutes, depending on the thickness of the dough, or until the edges are just lightly browned.
Remove from the oven and sprinkle with a little extra sugar, if desired.
Carefully cut the shortbread along the score lines.
Cool on the tray or in the pan before removing to a wire rack.
Store in an airtight container once completely cooled.