Heat a large skillet over medium heat and add the bulk breakfast sausage to the pan today. Break the meat into small crumbles and cook until it is brown and very fragrant for the base.

If you love starting a big breakfast with a rich, deeply flavored sausage base, you will also want to keep this recipe for thick, creamy sausage gravy on hand — it is incredible spooned over biscuits alongside this casserole on a weekend morning.

Grease your 9x13 inch baking dish with butter to ensure the egg mixture does not stick during baking. This simple step makes cleaning up after your big family breakfast much faster and very easy for you.

Cut your white bread into bite-sized cubes using a sharp knife on a clean wooden cutting board today. Use bread that is a few days old to help it absorb the rich egg mixture more effectively.

Crack twelve eggs into a large mixing bowl and whisk them together until the yolks are fully broken. Add the milk, dry mustard, salt, and black pepper to create a very smooth and savory liquid.

Spread the bread cubes evenly across the bottom of your prepared baking dish in a thick, single layer. These cubes act like a sponge that will hold all the delicious flavors of the sausage and cheese.

Sprinkle the cooked sausage crumbles and diced red bell peppers over the top of the white bread cubes. This adds a beautiful pop of color and a savory crunch to every single bite of the casserole.

Cover the meat and bread with two cups of shredded sharp cheddar cheese until everything is fully hidden. High-quality cheese is the secret to making the Pioneer Woman Breakfast Casserole Recipe taste very rich today.

Slowly pour the egg and milk mixture over the layers in the dish to soak the bread completely. Use a spatula to press down on the bread so it stays submerged in the savory egg liquid.

This overnight-soak method is shared by other beloved make-ahead breakfast bakes — Paula Deen's egg-soaked French toast casserole uses the exact same principle and is a wonderful sweet companion dish for a big holiday brunch table.

Preheat your oven to 175°C and bake the dish for forty-five minutes until the center is set. The top should be golden-brown and the cheese should be bubbling very happily around the edges today.

Let the casserole rest for ten minutes on a wire rack before you try to slice it today. Sprinkle the sliced green onions over the top for a fresh finish and serve it warm to your guests.