Prep Time: 25
Cook Time: 50
Serves: Serves: 8
Toast the bread; cool and cut into cubes. (You will have about 7 cups cubed toast.) Place in a very large bowl. Stack cheese; cut stack into 6 strips and add to bowl. Add corned beef and sauerkraut. Toss well and transfer to a greased or sprayed 13 x 9-inch baking dish or 2-quart shallow casserole dish.
In a large bowl, beat eggs with mustard. Whisk in milk until well blended; pour over mixture in dish. Let stand 15 minutes, pressing down on solids so milk moistens the toast on top of casserole. (At this point mixture may be covered and chilled up to 24 hours before baking.)
Bake uncovered in a preheated 350°F oven 45 to 50 minutes or until puffed and golden brown.