My nieces are very into the Disney Princesses. My niece Emily wanted a Snow White Birthday Cake. I have done other similar cakes, like Barbie using a special doll top that can be purchased at a craft store that is designed for use on a cake. They have as spike instead of legs.
This would not work for the Snow White cake because I could not find a cake topper that looked enough like Snow White to pull it off. I knew it would have to be just right. I found a Snow White doll and removed her clothes and then shoved the doll into the cake up to her waist.
The cake was baked in a large metal bowl. I made another four inch round cake to place on top of the bowl to give the necessary height to allow the doll to sink in all the way to the waist.
Then I used butter cream frosting and a star tip to cover the cake and the doll so that it looked like her dress.