I made this for my son’s birthday party. It was simply two 9×13 single-layer cakes. Right after baking, I covered the bottom with a piece of waxed paper and flattened out with my hand so it wouldn’t bulge in the middle (I never cut them flat because the squished cake tastes so yummy and moist!). I froze both pieces to make them easier to work with (and because freezing makes the cakes more moist).
I frosted the entire bottom cake, then propped the upper one on a piece of cardboard held up by a couple of wooden skewers cut to size. It was difficult to get it to stay in place, but once I positioned it, I used more skewers to anchor it. I frosted all and made the gold bands using a wide flat tip (I never use fondant because it detracts from the taste, so it is all butter cream). On the inside of the cake, I stuffed a bunch of chocolate “gold” coins and treasures from World Market.
The little pirates loved the cake–getting pieces of chocolate treasure with each piece made it amazing, although I sometimes wonder how all the parents felt.