Egg White Breakfast Casserole

I love whipping up egg casseroles to have an easy breakfast during the week. It reheats well, is healthy and high protein, and is filling. I had lots of egg whites in my refrigerator that were leftover from using just egg yolks in ice cream recipes, so I decided to use them all up in this breakfast casserole. You can also use store-bought egg whites from the carton as well! You will LOVE this Egg White Breakfast Casserole – it’s so flavorful and easy! It has italian sausage, lots of veggies, and some savory parmesan cheese (omit if dairy-free!). It’s an easy go-to recipe for sure.

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Nutritional benefits of this recipe

• Although egg yolks are what provide the majority of nutrients in an egg, egg whites are rich in protein. This recipe is a great way to use up egg whites if you’ve had to use egg yolks for other recipes such as ice cream.
• This recipe has lots of veggies – bell pepper, onion, spinach, and mushrooms. These veggies add fiber, vitamins, minerals, antioxidants, and polyphenols.
• For the healthiest dairy products (butter and milk for this recipe), I always recommend buying grass-fed. Better yet, if you can support a local farm that has grass-fed cows and dairy products, then do that!

Ingredients for Egg White Breakfast Casserole

Egg whites – I used leftover egg whites from making several batches of homemade ice cream since ice cream only uses egg yolks (see my ice cream recipes here). So I had only 24 oz of egg whites, and it turned out great! But if you buy the usual 32 oz carton of egg whites from the grocery store, then you can use the entire carton and just bake it on the longer end of the time (possibly a few minutes extra – just until the center is completely set!).

Italian sausage – I used Mulay’s mild italian ground sausage. You can also use sausage links and just cut or dice them up.

Onion – I used half of a yellow onion.

Bell pepper – I used a large red bell pepper.

Mushrooms – optional

Spinach

Parmesan – or other shredded cheese of choice, or omit for dairy-free.

Milk – I use whole grass-fed milk but you can sub dairy-free if needed.

Salt

Granulated garlic

How to make Egg White Breakfast Casserole

1. Preheat a skillet to medium-high heat with a little avocado oil, tallow, or butter. Add the diced onion, bell pepper, and mushrooms and cook 3-4 minutes. Add the ground sausage and cook until no longer pink, about 6-8 minutes, breaking it up as it cooks. Incorporate the chopped spinach and cook for a minute or two until wilted.
2. Grease the bottom of a 9×13 baking dish and layer the cooked veggies and sausage mixture on the bottom. Sprinkle the shredded parmesan cheese over top.
3. In a large bowl, whisk together the egg whites with the milk, salt, and granulated garlic. Adjust the salt as needed. My ground sausage already had salt so 1/2 tsp was sufficient for my casserole.
4. Carefully pour the egg white mixture into the baking dish over top of the base mixture.
5. Bake at 350ºF for 45-50 minutes, or until the center is completely set.
6. Let it rest for 10-15 minutes before slicing.

Modifications and variations

• I only had 24 oz of egg whites on hand, but you can absolutely use an entire 32-oz container of egg whites if you have store-bought egg whites.
• You can use sausage links instead of ground sausage and just chop it up.
• Substitute or add other veggies, such as sun-dried tomatoes, leeks, fennel, etc.
• Substitute any other cheese in place of the parmesan, such as cheddar, mozzarella, gouda, etc.
• To make the recipe dairy-free: Omit the cheese and use a dairy-free milk.

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I hope you love this Egg White Breakfast Casserole! Please be sure to leave a comment and a rating if you give this recipe a try. I would love to know how it turned out for you!

Egg White Breakfast Casserole

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An easy go-to recipe to use up egg whites that is high-protein, veggie-packed, and delicious. You will love this Egg White Breakfast Casserole!

• Author: Christine Manes
• Prep Time: 15 minutes
• Cook Time: 50 minutes
• Total Time: 1 hour 5 minutes
• Yield: 8 servings 1x
• Category: breakfast
• Method: stovetop, oven

Ingredients

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1/2 Tbsp avocado oil

1/2 onion, diced

1 large red bell pepper, diced

3–4 baby bella mushrooms, diced

1 lb ground italian sausage (or chopped sausage links) – I use Mulay’s

2 handfuls spinach, chopped

1 cup shredded parmesan cheese (or other type)

24 oz egg whites (3 cups) – or use a 32 oz carton of egg whites, see note

1/2 cup milk

1/2 tsp salt

1/4 tsp granulated garlic

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Instructions

1. Preheat a skillet to medium-high heat with a little avocado oil, tallow, or butter. Add the diced onion, bell pepper, and mushrooms and cook 3-4 minutes. Add the ground sausage and cook until no longer pink, about 6-8 minutes, breaking it up as it cooks. Add the chopped spinach and cook for a minute or two until wilted.
2. Grease the bottom of a 9×13 baking dish and layer the cooked veggies and sausage mixture on the bottom. Sprinkle the shredded parmesan cheese over top.
3. In a large bowl, whisk together the egg whites with the milk, salt, and granulated garlic. Adjust the salt as needed. My ground sausage already had salt so 1/2 tsp was sufficient for my casserole.
4. Carefully pour the egg white mixture into the baking dish over top of the base mixture.
5. Bake at 350ºF for 45-55 minutes, or until the center is completely set.
6. Let it rest for 10-15 minutes before slicing.

Notes:

• I only had 24 oz of egg whites on hand, but you can absolutely use an entire 32-oz container of egg whites if you have store-bought egg whites.
• You can use sausage links instead of ground sausage and just chop it up.
• Substitute or add other veggies, such as sun-dried tomatoes, leeks, fennel, etc.
• Substitute any other cheese in place of the parmesan, such as cheddar, mozzarella, gouda, etc.
• To make the recipe dairy-free: Omit the cheese and use a dairy-free milk.

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