Grease a 9x13-inch baking dish and preheat oven to 350°F.
Brown the sausage in a large skillet over medium heat, breaking it into crumbles. Drain excess fat and set aside.
Layer the cubed bread in the prepared baking dish, then top with cooked sausage and 1½ cups of the shredded cheese.
In a large bowl, whisk together eggs, milk, dry mustard, salt, pepper, and paprika until well combined.
Pour the egg mixture evenly over the bread and sausage. Press down gently with a spatula to ensure bread absorbs the liquid.
Cover and refrigerate overnight, or let sit for at least 30 minutes if baking right away.
Bake covered with foil for 30 minutes, then remove foil, sprinkle with remaining ½ cup cheese, and bake uncovered for 15 minutes more until golden and set.
Let rest for 5 minutes before cutting into squares and serving warm.