Iris and Walter and Baby Rose by Elissa Haden Guest

Iris thought that having a baby sister would be just like playing with a doll. But newborn Baby Rose is a crabby cake. She fusses and cries and wails so much that Iris decides she needs a new baby sister. But with a little help from her family and her best friend, Walter--and with the passage of time--Iris discovers that being a big sister can be fun . . . some of the time!