I've been making a very similar recipe that my Mom would make every Christmas. I had been searching to find where the recipe came from and this seems to be it. In Pennsylvania, we call them Michigan Rocks. Now I know where the name comes from. The only variation is that I add raisins to match the amount of dates. I know a few people who add whiskey.
One tip: Put cold cookies in the microwave (about 10 seconds or so for one cookie, 15 seconds or so for two, etc.). You'll think they just came out of the over. Fruit is so warm.