In the scene where the 3 fairies are making Rose a dress and a cake notice the recipy. When the green one is doing the cake herself she reads the recipy and it says 'two eggs.' However, when the cake is made with magic, three eggs magically go into the cake.

Also notice when the other two fairies are fighting over the color of the dress. They are shooting magical beams that turn the dress pink or blue. But when the beams hit all the other objects in the house, they dont change color.