This is a remix of http://www.thingiverse.com/thing:185502 made by smartroad which is a great design.
I was going to print it as is but being tight and impatient I decided to mod it to cut down on plastic and printing time.
I have removed 7mm from the height of the cutter from the middle and I have also made the outer edge round and a bit small.
The original is a much better looking cutter but the mod should not effect its performance and save a bit of plastic.
I have uploaded files to print them on there own or together which is how I printed mine.
Thanks to http://www.thingiverse.com/smartroad/designs who also included a Recipe for Shortbread in his instructions ;) which I used but did not get as good a bake as smartroad so will keep trying ;)
My chief tester liked them and they did not last long.
I printed mine in natural PLA both at the same time on an over sized reprappro mendel at 0.2 layer height and 40% fill.
Printed the file with both cutters on the bed and it took 2 hours but I have slowed my machine down a bit to cut vibration due to 300 x 300 bed.
check out the original source which has a Recipe for Shortbread in the instructions and get printing then baking (give it a like while you there)