Nice and simple. Pound cake recipe (see Cthulhu cake), multiplied by 2.5 to fill a 10inch square tin.. This really did fill the tin, x2 would probably be just fine.

Leveled out and cut in half with jam in the centre. Crumb coated and then covered in fondant.

21 made out of fondant. All piping done in butter icing. Dusted with edible glitter to finish.