Willa Cather is an author whose work is so inextricably linked to a specific time, place, and culture; even though I really enjoy her writing, I always wonder if a more diverse audience appreciates it as much as I am able to. Her novels are really the ultimate Great Plains fiction, providing a fictional account of the Scandinavian immigrant experience in the Midwest. For fans of Karen Russell, recall her utterly sinister story "Proving Up" from Vampires in the Lemon Grove, which I loved as it immediately brought to mind Willa Cather, albeit a more macabre version.
I read My Antonia immediately after college, as one of the first books I read entirely for my own enjoyment. It's the kind of book you should enjoy all in one big gulp in a hammock on a breezy day.
O Pioneers! is my favorite of her novels, the story of Alexandra Bergson and her tireless and lifelong efforts to maintain the family farm she inherited from her father. When I think about myself as an old woman, I usually imagine myself through the Willa Cather lens, as a deeply tan and wrinkled German immigrant living alone on a farm. This has very little basis in reality, but her writing about the American/Midwestern experience feels so timeless and epic that everything she writes starts to feel like an inevitability. I would call her the female John Steinbeck, but that's doing her a disservice because her work is entirely her own; that said, if you enjoyed John Steinbeck's Great American Novels, you will probably enjoy Willa Cather as well.