I decided to go ahead with the King Arthur Peppermint Bark cookies as mentioned in this post, since it really did just look like shortbread and I know how to do that.
The cookie part came out fine; it's not sweet and I very much appreciate that. The crushed peppermint from a bag did not do so well (store was out of candy canes and mints). I tried to get the bigger pieces, but even those were pretty small, and they melted and leaked out of the cookies, leaving holes (oven temperature is accurate per thermometers). The bigger pieces behaved well, though. Actual roughly-broken chunks of a candy would do better, I expect.
Would I make it again? Probably not. I think I'd rather just make normal shortbread cookies, dip those in chocolate, and coat with crushed peppermints.
