Mix ingredients in the order given. Pour into a greased 1 1/2 qt. baking dish and set in a shallow pan of hot water. Bake in preheated 350 degree oven about 1 hour or until set. Serve hot or cold.
For those of us who like our Reuben sandwiches a little differently.
Crumble corned beef into well-greased 12x8-inch glass dish. Spread dressing, then sauerkraut. Cover with cheese. Toss crumbled bread with margarine; sprinkle on top. Bake at 350 degrees for 30 minutes or until hot and bubbly.