When making a cake with any sort of hight or unusual shape to it you need a good dense cake, that will not crumble super easily. Box cake mix is not that cake I have learned this lesson over and over again. So then I needed to find a good recipe for cake that WAS that cake and still tasted good and was simple to make. I have not found one I would swear by. But I did find a way to make box cake denser. I tried it for the Treasure Chest cake I made for The Girl's sixth birthday party.
It was awesome!
So here is how to do it.
1 box of cake mix
1 package of pudding (the smaller one, match the flavor to your cake if you can if not vanilla works)
1/3 cup oil
1/2 cup whole milk
It will make a much less puffy cake as it is denser so for the purpose of the treasure chest cake I made two and had some leftover.
For the treasure chest cake you will need:
13x9x2inch cake. Chocolate works best so if you get cake crumbs in your chocolate frosting its not really obvious.
Gold foil wrapped candies
Fruit by the foot
Now to make it:
Cut a two inch section from the center of your cake. Cut that section in half on the diagonal leaving you to 9in triangle wedge shaped cake pieces.
Frost one of the large pieces of cake then add one of your wedges, angle side to the back of the cake, about an inch from back of the cake and frost it too.
frost the other large piece of cake this will be your lid. once frosted move it onto the other cake resting on the ramp you created with the wedge of cake.
Now you can fill your open treasure chest with candy treasures and decorate with leather straps and things.
A better tutorial video is here