These were an experiment - I've never made shortbread before and definitely have not made icing from scratch before. The cookies themselves turned out fairly well. They ended up a tiny bit dry, but fortunately for them the icing mostly cancels that out.
That icing, by the way, is the best kind. It's mostly powdered sugar and it starts off kind of drippy, but dries hard after it's melted a bit to become smooth on the cookie. The cookies I frosted last ended up with lumpier icing, since it had been sitting out longer.
Overall, though, I'm pretty happy with how they turned out.