Anita Jeram

It's kind of nice in that it's the story of a male authority figure performing the typically "motherly" task of putting a child to sleep. And this is very easily relatable, with nothing explicitly saying that Big is Little's father, or grandfather, or uncle, or anything specific. But because it's so generic, there's not much to it. Basically, the kid keeps telling the adult, "I love you this much," and the adult keeps responding, "Well, I love you this much," and it's always more.