In a Dutch oven, melt butter over medium heat; add rice, onion, carrots and raisins. Cook and stir until onion is tender, 5-7 minutes. Add broth and onion salt; bring to a boil. Reduce heat; cover and simmer until liquid is absorbed and rice is tender, about 20 minutes. Stir in peas, wild rice and cashews; heat through. If desired, sprinkle with green onions.