Combine first 5 ingredients in a large bowl; stir well. Spoon into a lightly greased 11" x 7" baking dish. Top with crushed crackers. Drizzle with melted butter. Bake, uncovered, at 350° for 25 to 30 minutes or until bubbly. Let stand 10 minutes before serving.
*You can crush the crackers while they're still in the sleeve; then open at one end, and sprinkle over casserole.