Overnight Breakfast Casserole with Sausage is a great, easy make ahead breakfast recipe! With basic ingredients like bread, sausage, cheese, and eggs, it's a hearty meal and the best idea for an easy Christmas morning breakfast.
Remove crusts from white bread and tear into 1" chunks. Layer in the bottom of a 9×13" baking dish greased with cooking spray or butter. Layer cheese over bread; add drained sausage over cheese.
In a large bowl, whisk together milk, eggs, salt, pepper, and mustard until blended. After you stir, pour this egg mixture over the top of the casserole, ensuring all of the bread is soaked.