Double Chocolate Sweetheart Cake (Really the Final Word in Chocolate Cake)

As a chocolate consultant for a major food company, I was once asked how I would make a cake taste the most chocolatey possible if I had no limitations. This question, delightful to contemplate, was particularly interesting because cocoa makes the most chocolatey-tasting layer cake but chocolate mixed only with cream offers the fullest chocolate sensation. My answer was that I would make a cocoa layer cake with all yolks (which give the best flavor) and then inject it with my favorite ea