Cook mushrooms in butter in a large skillet over medium heat 5 minutes, stirring constantly. Add rice, cook 2 minutes. Stir in broth; bring to a boil. Cover, reduce heat, and simmer 20 minutes or until liquid is absorbed and rice is tender.
Combine peaches and lemon juice; toss. Add peach mixture, cashews, and sliced green onions to rice mixture, and stir gently. Spoon rice mixture into serving dish and garnish, if desired, with lemon wedges and/or green onion fans.