The book I am searching for was a children’s chapter book that I read in the 1950s.
The story was a retelling of the Cinderella story from the point of view of a young boy (Teddy?) who makes his way into the palace where they are getting ready for the ball. He and the rather silly king get in the way of the queen. They go on to have an adventure that at one point involves a mound of butter and buttons (pictured in what I remember as a pen & ink illustration). At some point the boy unlocks the palace gate with a small key. I believe it is indicated at either the beginning or end that the story is the boy’s dream – perhaps he dozed off while reading the fairy tale?
It had, of course, the ubiquitous blue cover. I think it was a hardback about 6”x8” but memory may be failing me.
My childhood copy was destroyed years ago and I would love to read the book again.