It's pretty much just like it sounds. Someone brought these in from the Momofuku Bakery and Milk Bar, and they are my new favorite cookies in the EV, if not the entire city. The linked article is outdated, but there are lots of gratuitous mouth-watering photos.
Clockwise from top left: Compost cookie, Peanut Butter Cookie, Cornbread Cookie and Cornflake Marshmallow cookie. WTF, universe? This RULES.