Using a 2 quart casserole dish with lid, put rice, hot water, butter and salt in dish. Stir. (I put my casserole dish on a plate in the micro as sometimes the water boils over a little. Saves cleanup after).
Cover, and microwave on high power 5 minutes. Stir with fork (careful watch the steam!)
Cover and put back in microwave and cook on medium this time for 15 minutes.