For Biddle's Sake is a story about a girl named Parsley who will eat nothing but parsley.  She  gets taken home by a fairy whose only wish is to see Parsley's smile, which everyone loves. Unfortunately,  the fairy likes to turn things into frogs. One day the fairy turns parsley into a frog and is very upset. Will Parsley ever turn back to her real form? 

Try reading The Fairy's Mistake, The Princesses test, Princesses Sonora and the Long Sleep, Cinderellis and the Glass Hill, and the Fairy's Return in the same series, The Princesses Tales.( you don't have to read them in order!)