Lightly spray a 9"x13"x2" casserole pan with non stick spray.Whisk together the eggs, milk, dry mustard and salt until combined, set aside.Fill the bottom of the casserole dish with half of the crusty bread. Then top with half of the cooked sausage and half of the cheese. Sprinkle with half of the black pepper. Repeat with the remaining bread, sausage, cheese and pepper.Pour the egg mixture all over the casserole dish. Cover and place in fridge for 8 hours.In the morning preheat the oven to 325 degrees F.Top the casserole with the tater tots in an even layer and bake for 60 to 70 minutes or until the center of the casserole is set.Let sit for 10 minutes before cutting. Serve with the optional toppings if desired. Enjoy!