I have made this cake for the past several years with unfailing applause. I got the recipe from Cooks Illustrated. Do not substitute semisweet chocolate chips for the chopped semisweet chocolate in the frosting—chocolate chips contain less cocoa butter than bar chocolate and will not melt as readily. For best results, don't make the frosting until the cakes are cooled, and use the frosting as soon as it is ready. If the frosting gets too cold and stiff to spread easily, wrap the mixer bowl with a towel soaked in hot water and mix on low speed until the frosting appears creamy and smooth. Refrigerated leftover cake should sit at room temperature before serving until the frosting softens. Recipe for the wonderful Frosting is on this site "The Very Best Chocolate Fudge Icing"