I made these to bring into my final thesis seminar meeting. Of course we already handed in our theses, so this was just a celebration. Since it is still Passover, I had to do something flourless and I didn't want to make macaroons again. So I made these amazing flourless chocolate cookies from Francois Payard's Chocolate Epiphany
Basically, these cookies are powdered sugar, cocoa powder, egg whites, and ground/chopped walnuts. The trick is to not over mix them. If you do the egg whites stiffen a bit too much and the cookies end up puffier and a little less brownie-like in the center. That said, I tend to over mix them a bit, and I still love them, so don't worry too much. Just know that they won't look as even and flat as his do in the book. FYI, I make mine smaller than he calls for, just because I like being able to have two cookies but not be piggy. If you do that, just make sure to check them often, as they'll bake quicker.