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Overnight Breakfast Casserole with Sausage

This overnight breakfast casserole with sausage is one of my go-to easy breakfast recipes! The perfect dish to make for holidays or Sunday brunch. 

Piece of breakfast casserole on plate.
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Perfect Breakfast for a Crowd

If you’re looking for an easy make ahead breakfast recipe that’s great for serving a crowd, this overnight breakfast casserole is perfect for you! It can be made the day before and is full of flavor, just like my favorite breakfast casserole in crockpot, crescent roll breakfast casserole or tater tot breakfast casserole.

It has tons of flavor…especially from the breakfast sausage and green chiles. They really help to take the taste up a notch. Some of the other breakfast casserole recipes that I’ve tried before are kind of bland, but this dish is anything but that!

I also love it because you can prepare the recipe the day before, refrigerate it overnight and then pop it in the oven on a holiday morning. We love to serve it for Christmas and Easter brunch. So yummy and very filling!

Why This Recipe Works

  • Make ahead. The beauty of overnight breakfast casserole recipes like this one or my overnight French toast is that all the hard work is done in advance, meaning you can enjoy your morning with family instead of slaving away in the kitchen!
  • Feeds a crowd. Big enough for 8 generous servings, this overnight sausage breakfast casserole is absolutely perfect for feeding a crowd. You can even make two casseroles if you have a larger gathering.
  • A holiday favorite. This is the perfect breakfast to serve on Easter, Thanksgiving or Christmas morning. My family looks forward to it every year!

Recipe Ingredients

Find the full printable recipe with specific measurements below.

  • Sausage: Breakfast sausage adds great flavor and protein.
  • Veggies: Chopped onions, bell peppers, potatoes and green chiles are sauteed in butter, making them perfectly tender and flavorful. I also like to sneak in some chopped spinach before baking for more veggies.
  • Eggs: Make sure you’re using large, fresh eggs for the best flavor and texture. These get mixed with a little bit of milk to make them creamier, as well as a dash of salt and pepper.
  • Cheese: A sprinkle of shredded cheddar cheese on top is the perfect finishing touch for this sausage breakfast casserole. It gets nice and melty as it bakes!


This overnight breakfast casserole with sausage is such a versatile dish that can be adapted to fit your needs.

You can substitute baked ham or bacon for the sausage or can swap in different veggies like mushrooms, broccoli or chopped asparagus depending on what you have on hand. Instead of diced potatoes, feel free to use hashbrowns like I did in this breakfast hashbrown casserole. So easy and customizable!

How to Make a Breakfast Casserole Overnight

Showing how to make an overnight breakfast casserole in a 4 step collage.
  1. Sauté. Brown the meat in a frying pan and add to a bowl once finished. Then add butter to the same pan and mix in the onions, bell peppers and potatoes until tender. Pour in the green chiles, as well as the cooked sausage. Then transfer the mixture into a buttered 9×9″ baking dish and place in the fridge to chill slightly.
  2. Pour. In a medium bowl, whisk together the eggs, milk, salt and pepper. Then pour the eggs over the sausage mixture in the baking dish.
  3. Top. Next, sprinkle spinach over the top. Then add the shredded cheese. Cover with foil and store in the fridge overnight.
  4. Bake. When ready to bake, preheat the oven to 325°F and bake for 45 minutes. Remove foil and bake additional 10-15 minutes, or until toothpick comes out clean. Before serving, let stand for a few minutes to set completely.

5 star review

“Delicious & easy!! Skipped the green chilies (couldn’t find any) and left out the cheese (this way, family could add whatever cheese that they wanted after it was done baking in the oven), and it turned out great. Family loved this. Will make again.”

– Jane
breakfast casserole recipes

Favorite Sides for Serving

If you’re hosting a big brunch for a crowd and are looking for sides to serve alongside this breakfast casserole, below are a few ideas!

Recipe FAQs

How long can a breakfast casserole be refrigerated before baking?

Once prepared, this overnight breakfast casserole can be stored in the fridge for about 24 hours before baking.

How much longer do you cook a refrigerated casserole?

I don’t typically cook mine for any longer than usual, however I will let it set on the counter while the oven is preheating so that the eggs can come slightly to room temperature before baking.

How do you know when it’s done?

It will be done when the outside edges are slightly golden and the egg mixture stays firm when you gently rock the pan from left to right.

You want to make sure the egg mixture has cooked all the way through and isn’t still liquefied in the center. To double check, stick a knife in the middle of the casserole. The knife should come out clean if cooked completely.

What’s the best way to serve overnight breakfast casserole?

You can serve plain, or add toppings such as sliced avocado, salsa, cilantro or sour cream.

Storing + Reheating Leftovers

  • Storing: Any leftovers will keep in the fridge for about 3-4 days. Make sure to cover your pan with a lid or wrap tightly in aluminum foil or plastic wrap.
  • Reheating: You can either warm for a few minutes in the microwave or the oven. If using the oven, I would recommend covering with foil so the top doesn’t brown too much.
Breakfast casserole cut into squares in pan.

Looking for more easy breakfast ideas? Try my breakfast casserole with biscuits, cheesy ham and broccoli frittata or this delicious sausage breakfast pizza.

More Breakfast Recipes to Try

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breakfast casserole

Overnight Breakfast Casserole

5 from 30 votes
↑ Click stars to rate now!
Author: Jamielyn Nye
This overnight breakfast casserole with sausage is one of my go-to easy breakfast recipes! The perfect dish to make for holidays or Sunday brunch. 
Prep Time: 20 minutes
Cook Time: 1 hour
Total Time: 1 hour 20 minutes
Servings: 8


  • ½ pound breakfast sausage
  • 2 Tablespoons butter
  • ½ cup chopped onion
  • 1 cup chopped bell peppers
  • 1 ½ cups frozen potatoes (cubed or shredded, thawed)
  • 4.5 ounce can chopped green chiles
  • 8 large eggs
  • cup milk
  • 1 teaspoon Kosher salt
  • ¼ teaspoon ground black pepper
  • ½ cup chopped spinach (optional; add more if desired)
  • ½ to 1 cup shredded cheddar cheese


  • Butter a 9×9" (or 8×10") baking dish and set aside. Cook the meat in fry pan over medium heat. Once cooked through, remove to a bowl.
  • Add butter to the pan with the onions. Cook for 2 minutes. Then add the bell peppers and cook an additional 2 minutes.
  • Next mix in the potatoes and cook until heated through, about 3 minutes. Stir in the sausage and green chiles and then pour into the baking dish. Place in the refrigerator to cool slightly, before adding the eggs.
  • Whisk the eggs, milk, salt and pepper in bowl. Then pour over the sausage mixture in the baking dish.
  • Sprinkle chopped spinach over the top. Next add the cheese. Cover with foil and then refrigerate until ready to bake.
  • When ready to bake, preheat the oven to 325°F. Set the pan on the counter while the oven is preheating. Then bake for 45 minutes. Remove foil and cook an additional 10-15 minutes, or until a toothpick comes clean. Let stand a few minutes before serving and then slice.



Make ahead: This dish can be made up to 24 hours in advance. Simply cover and refrigerate before baking. This also makes a great dish to bake and serve throughout the week. Once baked, store leftovers for up to 4 days. 
  • Meat: You could also substitute with ground turkey or Italian sausage. You could even substitute with diced ham or bacon too.
  • Vegetables: Feel free to add in any vegetables you’d like. Some of my favorites to add are mushrooms, chopped asparagus or broccoli. 


Calories: 211kcal | Carbohydrates: 28g | Protein: 7g | Fat: 7g | Saturated Fat: 3g | Cholesterol: 173mg | Sodium: 417mg | Potassium: 301mg | Fiber: 1g | Sugar: 1g | Vitamin A: 1120IU | Vitamin C: 29.5mg | Calcium: 53mg | Iron: 2.2mg

Nutrition provided is an estimate. It will vary based on specific ingredients used.

Course: Breakfast
Cuisine: American

Did you make this recipe? Don’t forget to give it a star rating below!

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