My Moist Chocolate Cupcakes with Vanilla Buttercream recipe works really well in cake form. Simply divide the batter equally between three 8" round cake pans and cook for 20 minutes at 350 degrees, or until a toothpick inserted comes out clean. I use the same frosting recipe as with the cupcakes, and frost it all up once the cakes are cool.
P.S. The cakestand and paper liner are from Martha's Collection at Macy's. (I think they're only available in stores, not online).