This make-ahead breakfast casserole is delicious, easy to make, and big enough to serve at gatherings.
Brown sausage and drain excess grease.
While sausage is cooking, stack bread and cut into squares using a sharp knife. Set aside.
Whisk together eggs and milk.
Use cooking spray to cover 2 quart casserole dish. Cover bottom of dish with half of the bread and sausage, 1/2 cup of cheese, salt, pepper, and dry mustard. Repeat layers.
Pour egg mixture on top, making sure to cover the entire casserole. Top with slices of butter. Cover dish and place in refrigerator overnight.
Next morning, preheat oven to 350 degrees.
Bake uncovered for 40 minutes or until casserole is cooked through.
Top casserole with remaining cheese and place back in oven for 5 minutes or until cheese is melted.