Why exactly are these cookies bestowed with such a lofty name as truffles? Well, first there's the generous amount of butter, cocoa powder, and sugar in the dough, which also includes two eggs (for richness and extra moistness) and vanilla extract (for inimitable flavor). Then there's the shape of the cookies (balls) and their coating of powdered sugar, which makes them resemble the real deal. And they are utterly delicious.