Vermont College of Fine Arts in the Writing for Children and Young Adults department, Sharon Darrow, has published a book of her lectures.
When I offered a picture book manuscript in a workshop at VCFA run by her, she told me that it read more like the outline of a middle grade novel than a picture book, which changed my whole view of it. And I spent the next few semesters enlarging it and building the world where those characters lived.
So, if you'd like to get a taste of the kinds of things we learn in this graduate course about writing, I highly recommend her book, Worlds within Words, Writing and the Writing Life.
You can read a smidgen of it here on the Cynsations blog