Cover rice with water in suce pan and bring to a boil,. remove from heat. Let soak 1 hour then drain. Melt 3 tbs of butter in skillet add mushrooms and onion saute over medium heat until lightly brown. In a large bowl combine rice mushroom mixture, and all remaining ingredients except butter. Turn into buttered 2 qt casserole. Cover and bake 350 degrees x 1 1/4 hour. Remove the cover and dot with butter and bake uncovered x 20 min.