Thaw; pour mixture into casserole dish and bake at 400 degrees for 30 minutes. Remove from oven and stir, being sure to scrape any rice that has collected along the sides and mix well.
If desired, sprinkle with 1/2 cup crushed cracker crumbs and drizzle 2 tablespoons of melted butter over crumb mixture. Return to oven and bake at 400 degrees for additional 45-50 minutes.