1. Preheat oven to 400°. Combine first 8 ingredients. Spoon mixture into a lightly greased 13- x 9-inch baking dish.
2. Combine crushed crackers and butter. Top casserole with cracker mixture.
3. Bake at 400° for 30 to 35 minutes or until bubbly and cracker mixture is brown. Let stand 15 minutes.