I made this cake for the birthday of a friend’s son. This was so fun to make, as was playing a lot of the game beforehand, for uh, research, yea that’s it…. strictly research! :) The domes are cake covered in marshmallow fondant. The water is blue-tinted piping gel, as are the blue insides of the piped stars on the message. The house is rice cereal treats covered in fondant. Mario and the star are gum paste.