Here's an easy shortbread recipe that I have discovered works well with Spritz cookie makers.
1/2 cup cornstarch
1/2 cup icing sugar
1 cup all purpose flour
3/4 cup butter
Sift dry ingredients together. Mix with butter using a spoon or your hands (or, I guess a food processor, we've never tried that.)
You can drop them and flatten with a fork, or roll them out or put them in a Spritz thing. Bake at 300 F for 15-20 minutes depending on thickness.
Or even longer - I like them a bit on the well-done side.