There is more than one way to build the inside of a cake topper, and both styrofoam (polystyrene) and rice cereal treats are commonly used.

Rice cereal treats are often chosen when an edible inner base is preferred. Styrofoam is also widely used in cake decorating, including for cake dummies, because it is lightweight, easy to shape, and gives a firm stable base. It can make the whole process quicker, cleaner, and a little more forgiving.

It is not edible, but when it is fully covered and kept separate from the cake, it can be a very practical option for this type of work. Many cake shops, including high-end ones, use it for exactly these reasons.

If you choose to use styrofoam inside your topper, follow the guidelines below to help keep the process clean and the finished topper properly separated from the cake.