To prepare in the microwave, place all the ingredients in a microwave-safe bowl and cook for 20 minutes. Stir and cook for 15 minutes more, or until the rice is done and all the liquid is absorbed. To prepare on the stovetop, if you’re using fresh mushrooms, saute in the butter for 5 minutes. Place all the ingredients in a saucepan and cover. Bring to a boil and reduce the heat to a simmer. Cook until all the liquid is absorbed, about 30 minutes.