Melt the butter over medium heat in a large skillet. Add the barley and onion and cook, stirring, until the onion is golden, 3 to 5 minutes. Add the broth, raisins, and oregano; bring to a boil, then reduce the heat to a simmer. Cover and cook until the barley is tender and the liquid is absorbed, about 45 minutes.

Add the apples, celery, and cilantro and cook for 5 minutes more. (If using ground coriander, hold off adding until the last 2 minutes of cooking.) Ladle into bowls to serve.