Preheat oven to 350°. Grease a 9"x13" pan. With an electric mixer, blend Eggs, Mustard, Milk, Salt and Pepper; set aside. Spread Croutons in the bottom of the prepared pan; sprinkle the Cheese on top of the Croutons. Pour the Egg mixture over the Cheese and top with the crumbled Bacon. Bake for 45 minutes to 1 hour.