I just made this today and they were wonderful. Smooth and creamy (and, yes, as he says, very potato-y) on the inside with a lovely browned exterior.
Here's the link to Bittman's blog where he tells how to make them:
I used small red potatoes from my favorite farmer at the Greenmarket. I didn't baste very much at all -- I mostly set the timer and left the potatoes alone. When it was time to turn them, I added a couple of tablespoons of vegetable stock (not required per the recipe). They were delicious.
Has anyone else tried them? Tried any variations?