I was thirteen when I had my first taste of snickerdoodles; junior high school cooking class. Loaded with butter, shortening, and sugar and then rolled in a sugar-cinnamon mixture, those first cookies were like none other I had ever tasted before. Never thought that they could be improved or made even more addictive, but somebody out there decided to add cocoa to this vintage recipe. When you bite into a chocolate snickerdoodle, brownie is the first thought that comes to mind. A very rich cookie, this recipe will have to be filed under 'the once in a blue moon' category.