Name: Overnight Breakfast Casserole
Prep time: 15 min
Cook time: 60 min
Total time: 75 min
Ingredients: 12 slices bread (such as challah, brioche or any egg bread, preferably day old bread); 1 tbsp olive oil; 1 large onion (chopped); 1 lb Italian sausage (casings removed); 1 tsp dry mustard; ½ tsp salt (or to taste); ½ tsp pepper (or to taste); 1 medium red bell pepper (finely chopped); 3 green onions (chopped); 2 cups cheddar cheese (shredded); 8 large eggs; 2 cups milk

This Overnight Breakfast Casserole is not only a crowd-pleaser but also a cook-pleaser because it’s so simple to make! For a special occasion or for any average day, this hearty delicious breakfast casserole is guaranteed to start anyone’s day off with a smile!

overhead shot of overnight breakfast casserole cut into pieces

If anyone was unaware of how much a I love all things breakfast – this casserole is sure to give you an idea! Breakfast casseroles are brilliant, especially when you can prep them the night before and simply pop them into the oven the next morning. It’s completely hassle free and the outcome is nothing less than delicious!

This casserole is super handy for numerous reasons; a crowd to feed over the holidays, a kids sleepover, or just in general if you’re looking for something new and easy! It’s loaded with flavor, baked to perfection, and certainly going to please everyone and anyone who puts it in their mouth!

Ingredients

Bread – I used 12 slices of brioche bread – breads such as challah or egg bread will also work great, and a day old is preferred!
Olive oil – For cooking purposes.
Onion – 1 large onion, chopped and 3 green onions, also chopped.
Italian sausage – Casings removed.
Dry mustard – Any brand of dry mustard will work great!
Salt and pepper – To taste.
Bell pepper – I used a red bell pepper, finely chopped but you can use whichever color you prefer!
Cheese – I used cheddar cheese today, shredded.
Eggs – Because breakfast casserole guys!
Milk – You can use whichever fat percentage you prefer.

process shots showing how to make breakfast casserole

How To Make Overnight Breakfast Casserole

Preheat oven: To 300 F degrees.
Prepare bread: Cut the bread into cubes and place them onto a baking sheet. Place the bread into the oven and bake for 10 minutes, just enough to dry the bread out but not toast it. Remove from the oven and set aside.
Prepare sausage: In a large skillet, heat the olive oil over medium heat. Add the onion and sausage and cook until onion has softened and sausage is cooked through. Use a wooden spoon to break up the sausage as it cooks. Finally, season with salt and pepper and dry mustard.
Build casserole: Add half the bread cubes to a 9 x 13 inch casserole dish and top with half of the cooked onions and sausage. Next, add half the chopped bell pepper, chopped green onions, and 1 cup of shredded cheese. Repeat layers with remaining bread, onion, sausage, bell peppers, green onions, and cheese.
Prepare the eggs: In a bowl whisk together the eggs and milk and pour over the casserole evenly. Finally, cover the casserole dish with aluminum foil and put in the fridge overnight.
Bake and serve: The next morning, preheat the oven to 350 °F and remove the foil from the casserole dish. Place into the oven and bake for 50 to 55 minutes. You’ll know the casserole is done if you insert a knife in the centre and if it comes clean, it’s done. Serve hot!

What Else Can I Add To This Casserole?

You can go nuts on this list, you guys! Just think of breakfast, what it means to you, and what your favorite flavors are! Here’s some suggestions:

Mushrooms
Potatoes
Bacon
Ham
Pulled pork
Jalapeño jack cheese
Ground beef

breakfast casserole in a white casserole dish cut into slices

How To Serve

Like I mentioned before, I am a breakfast connoisseur! There are so many things I would serve along side this casserole, and I don’t just mean the typical bacon, toast, maybe some hash browns – even though most of us love those things! I’m going all out with this dish! Here’s what I’m talking about!

How To Store Leftovers

Overnight breakfast casserole will last in the fridge for up to 4 days when properly sealed in an airtight container.

To extend the shelf life of the breakfast casserole I recommend putting into the freezer. Stored properly in an airtight container, it will last anywhere from 3 – 6 months frozen!

Reheating

You can reheat this breakfast casserole a couple ways.

Microwave – Put the casserole in a microwavable dish and reheat to desired temperature.
Oven – This is probably the best way to reheat this casserole. Cover it with aluminum foil and bake in the an oven preheated to 325 F degrees for about 15- – 20 minutes!

a slice of breakfast casserole on a white plate

More Drool Worthy Breakfast Ideas Here:

Jill Brant says

January 29, 2020 at 3:39 am

This casserole is fab!! Loaded with hearty ingredients it’s both moist, & full of flavor & very filling. So versatile & a breeze to assemble. My family really enjoy it! Once again Jo has hit it out of the park for us 😆 Cheers & Thanks Jo ~ you Rock!!