In a greased 3-quart baking dish, combine the broth, rice, 1 cup onions, soy sauce, butter and thyme. Cover and bake at 350 degrees for 65–70 minutes or until rice is tender.
Meanwhile, in a large skillet, sauté the cauliflower, broccoli, peppers, garlic and remaining onions in oil until crisp-tender; spoon over rice mixture.
Cover and bake for 10 minutes. Uncover; sprinkle with cashews and cheese if desired. Bake 5–7 minutes longer or until cheese is melted.