The Wind in the Willows (Kenneth Grahame book)
I loved this book. It’s beautiful, laugh-out-loud funny, incredibly cozy, and slightly trippy. It’s easy to see how it influenced later British fantasy and children’s lit (Winnie the Pooh, Redwall, LOTR, Narnia, and even Harry Potter to some extent), so it’s worth reading just for that. Warning: there’s a bit of mild, plot-irrelevant sexism, which should be easy to skip over if reading aloud to a kid.