This overnight breakfast casserole with sausage, potatoes, eggs and cheese is easy to assemble the night before and bake in the morning. It’s perfect for a holiday breakfast or when you have overnight guests!
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Best Breakfast Casserole Recipe
If you’re looking for an easy make ahead breakfast recipe that serves a crowd, this overnight breakfast casserole is perfect for you! It can be made the day before just like my favorite or tater tot breakfast casserole.
Unlike other breakfast casserole recipes you may have tried, it’s so flavorful from the breakfast sausage and green chiles. I love that you can prepare it the day before, refrigerate it overnight and then pop it in the oven on a holiday morning.
Why This Recipe Works
- Make ahead. The beauty of overnight breakfast casserole recipes like this one is that all the hard work is done in advance, meaning you can enjoy your morning!
- Feeds a crowd. Big enough for 8 generous servings, this overnight sausage breakfast casserole can feed a crowd. I love to serve it with berry fruit salad and silver dollar pancakes.
- A holiday favorite. This easy breakfast casserole recipe is perfect to serve for a Christmas morning breakfast or Easter brunch!
Ingredients for Breakfast Casserole
Find the full printable recipe with specific measurements below.
- Sausage: Breakfast sausage adds great flavor and protein.
- Veggies: Chopped onions, bell peppers, potatoes (diced or shredded) and green chiles are sauteed in butter, making them perfectly tender and flavorful. I also like to sneak in some chopped spinach before baking.
- 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!
Substitutions and Variations
This overnight breakfast casserole with sausage is such a versatile dish that can be adapted to fit your needs.
- Protein: You can substitute baked ham or bacon for the sausage. Try chorizo for some Mexican flavor.
- Cheese: Substitute a different type of cheese like sharp cheddar cheese, Monterey jack, colby or mozzarella.
- Veggies: Swap in different veggies like mushrooms, broccoli or chopped asparagus depending on what you have on hand.
- Potatoes: Instead of diced potatoes, feel free to use hash browns like I did in this breakfast hashbrown casserole. So easy and customizable!
- Salsa: Use salsa instead of green chilis if you would like.
How to Make Overnight Breakfast Casserole
- Sauté. Brown sausage and add to a bowl once finished. Add butter to the same skillet and saute onions, bell peppers and potatoes until tender. Pour in green chiles, and cooked sausage. Transfer the mixture into a buttered 9×9″ baking dish and place in the fridge to chill slightly.
- 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.
- Top. Next, sprinkle spinach over the top. Then add the shredded cheese. Cover with foil and store in the fridge overnight.
- 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
Once prepared, this overnight breakfast casserole can be stored in the fridge for about 24 hours before baking. I bring it slightly to room temperature before putting it in the oven by removing it from the fridge 30 minutes prior to baking.
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.
You can serve plain, or add toppings such as sliced avocado, salsa, cilantro or sour cream.
- 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.
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Overnight Breakfast Casserole
- 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
- ⅓ 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.
- 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.
Nutrition provided is an estimate. It will vary based on specific ingredients used.
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