This easy breakfast casserole is loaded with eggs, sausage, spinach, peppers, and of course, cheese! A slice of this veggie- and protein-loaded casserole will keep you full for hours. 

Other great breakfasts to keep you full longer are my healthy German pancakes, cheesy scrambled eggs, and breakfast quinoa.

A fork cutting into a slice of breakfast casserole.

Why This Recipe Works

Delicious breakfast recipes are staples in my house. And this easy breakfast casserole is a keeper because you can prep it the night before and bake the next morning AND you don’t have to sit by the stove or griddle babysitting your food while you get ready or get your kiddos up and ready. Pop this in the oven and let it bake while you get things done. 

Other breakfast options you can let the oven take care of are my oven-baked bacon, healthy German pancakes or baked oatmeal cups.

Ingredients Needed

Ingredients used to make breakfast casserole on a textured white background.
  • Sour cream: Sour cream is crucial to my easy breakfast casserole because it makes the mixture more moist and creamy, resulting in a creamy texture once baked. 
  • Spinach: I’d recommend using the bagged spinach that is pre-washed and ready to go. If not, be sure to thoroughly dry the spinach after washing it so you aren’t adding extra liquid to the mixture.
  • Pork sausage: Pay attention to the level of spice. You’re welcome to use any level of spice, just be sure to take note so you don’t end up with hot when you want mild! You can also use bacon instead of sausage if that is your breakfast meat preference.

Step-By-Step Instructions

  1. Whisk the eggs, sour cream, milk, and cheese until combined.
A glass bowl full of whisked eggs, cheddar cheese, milk, and sour cream.
  1. Cook the sausage and onion until browned. Use a wooden spoon to break the sausage into small bite size pieces as it cooks. Drain excess grease. 
Overhead photo of browned sausage in a skillet.
  1. Transfer the sausage mixture to the bowl with the egg mixture.
  2. Cook the peppers. Add a drizzle of olive oil to the now empty skillet, stir in the bell peppers and cook for 2-3 minutes. Stir in the spinach and cook an additional 30 seconds. The spinach will wilt slightly. 
Diced red and green peppers, and chopped spinach in a skillet.
  1. Transfer the cooked peppers to the egg mixture. Use a wooden spoon or spatula and mix everything together. 
A large bowl full of breakfast casserole ingredients against a white background.
  1. Pour the mixture into a 13″x9″ inch pan. Bake for 30-40 minutes or until the edges are set and the center is barely jiggly. Mine baked 34 minutes. All ovens are different so keep an eye on it. 
A glass 13x9 inch pan full of breakfast casserole.
  1. Remove from the oven and let sit for 5 minutes before slicing and serving. Store leftovers covered in the fridge for 3-4 days. Reheat individual servings in the microwave.

Recipe Tips

One of my biggest tips is to have the onion, peppers, and spinach chopped and diced before you begin. Doing so will make cooking this recipe a breeze.

Variations and Substitutions

Feel free to reduce the amount of sausage used. Rather than 2 lbs, opt for just 1 lb. Or if you want a healthier option, use ground turkey in place of the sausage. Granted, the flavor will change with any substitutions made.

Add more spinach, more peppers, or any other vegetable of choice.

If you want a spicier breakfast casserole, add diced jalapeños to the bell pepper mixture or use hot pork sausage.

Switch it up with the cheese! Use any cheese you have on hand: Monterey Jack, Colby Jack, or Pepper Jack cheese work beautifully.

FAQs

What is a breakfast casserole? 

It’s a breakfast dish made of primarily eggs, cheese, and in this case, sausage and vegetables. This recipe is loaded with onions, bell peppers, and spinach to be exact.

Can breakfast casserole be made the night before? 

Yes. Make up until it needs to bake. Rather than bake, cover the casserole and place in the fridge overnight. The next morning when ready to bake, remove the covering and bake according to the recipe instructions.

Why is my breakfast casserole runny?

It could be a few things: If you washed the spinach and didn’t dry it thoroughly, that would add additional liquid to the mixture. You could have added too much milk. Or your breakfast casserole could be runny because it isn’t baked all the way. Breakfast casserole should jiggle but not be runny when it is fully baked. 

Can I freeze a breakfast casserole?

Breakfast casserole is always better eaten right out of the oven, in my opinion. However, if you find yourself with loads of leftovers, you can freeze the casserole up to a month. Remove and let thaw before putting in the oven to warm thoroughly. 

How do you reheat egg casserole without overcooking it?

Be sure to cover the casserole with tin foil if you are reheating it in the oven. This will keep the casserole from burning on top while the dish is heating through. 

A slice of Breakfast Casserole on a plate.

More Mouthwatering Breakfast Recipes

A fork cutting into a slice of breakfast casserole.
Print Review
5 from 4 votes

Breakfast Casserole

This delicious breakfast casserole is loaded with sausage, eggs, spinach, peppers, and of course… cheese! One major bonus to this recipe is that it can be made the night before making breakfast the next day a total breeze.
Prep Time: 35 mins
Cook Time: 40 mins
Total Time: 1 hr 15 mins
Servings: 12 servings

Ingredients
 

  • 2 lbs pork sausage
  • 12 eggs
  • 1 cup sour cream - light or full fat
  • 1/4 cup milk
  • 1/2 cup onion - diced
  • 1 teaspoon olive oil
  • 1/2 green bell pepper - diced
  • 1/2 red bell pepper - diced
  • 1 cup spinach - chopped
  • 2 cups cheddar cheese - shredded

Instructions
 

  • Preheat oven to 350°F. Spray a 13×9 inch pan with cooking spray. Set aside. 
  • In a large bowl whisk the eggs, sour cream, milk, and shredded cheese until combined.
  • In a large skillet over medium heat add the sausage and onion and cook until browned, using a wooden spoon to break the sausage into small pieces as it cooks. Drain excess grease. 
  • Add the sausage to the egg mixture. 
  • In the now empty skillet add the olive oil and bell peppers. Cook for 2-3 minutes, then stir in the spinach and cook for 30 seconds. Spinach will wilt slightly. Remove from the heat. 
  • Transfer the cooked peppers to the egg mixture. Use a wooden spoon or spatula and mix everything together. 
  • Pour the mixture into the 13×9 inch pan. Bake for 30-45 minutes or until the edges are set and the center is barely jiggly. 
  • Remove from the oven, let sit for 5 minutes. Slice and serve. 
  • Store leftovers covered in the fridge for 3-4 days. Reheat individual servings in the microwave. 

Notes

To make ahead, prep the casserole up until baking point. Cover and place in the fridge. The next morning, remove the covering and bake as directed. 
One of my biggest tips is to have the onion, peppers, and spinach chopped and diced before you begin. Doing so will make cooking this recipe a breeze.
Variations/Substitutions:
Feel free to reduce the amount of sausage used. Rather than 2 lbs, opt for just 1 lb. Or if you want a healthier option, use ground turkey in place of the sausage. Granted, the flavor will change with any substitutions made.
Add more spinach, more peppers, or any other vegetable of choice.
If you want a spicier breakfast casserole, add diced jalapeños to the bell pepper mixture or use hot pork sausage.
Switch it up with the cheese! Use any cheese you have on hand: Monterey Jack, Colby Jack, or Pepper Jack cheese work beautifully.

Nutrition

Calories: 417kcal (21%)Carbohydrates: 3g (1%)Protein: 22g (44%)Fat: 35g (54%)Saturated Fat: 14g (70%)Cholesterol: 248mg (83%)Sodium: 680mg (28%)Potassium: 343mg (10%)Fiber: 1g (4%)Sugar: 2g (2%)Vitamin A: 1019IU (20%)Vitamin C: 12mg (15%)Calcium: 198mg (20%)Iron: 2mg (11%)
Course: Breakfast
Cuisine: American
Did you make this recipe?snap a photo and tag @saltandbaker in your posts and stories so I can see what you’re making!