A person's favorite author can change over time, depending on what you're reading, your mood, your life circumstances. It's a good question to visit from time to time as a writer. Knowing who your favorite author is can influence your point of view. Rereading a favorite author can inspire you. Writing down and studying favorite sentences by that author will make you a better writer.
E.B. White is a favorite of mine. I'm fascinated by his life. I study his style guide. And I'm enchanted by his fiction. He's a writer to whom I circle back time and again.
The first sentence of Charlotte's Web is often used as an example of a great way to start a story:
"Where's Papa going with that ax?"
It not only tells us about the characters but also creates enough tension to last an entire book. Reading White's fiction is a study in the style rules first outlined by his Cornell professor, William Strunk Jr. One of my favorites from The Elements of Style (Fourth Edition) is number 14 (from chapter V, An Approach to Style), Avoid fancy words. Fancy words aren't needed to address the concerns every child has about death. White shows how to "talk up" to your audience using language they will understand. Not easy, but in his hands it feels natural. He treats his reader with great respect.
There is something to be said for this quiet kind of writing. It is powerful. It's a thoughtful reflection of the "little book" that sits on writers' bookshelves everywhere.