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Chicken and Spinach Breakfast Casserole with Sun-Dried Tomatoes and Feta

Chicken and Spinach Breakfast Casserole with Sun-Dried Tomatoes and Feta makes for a delicious high-protein breakfast! Make it for breakfast, brunch, or meal prep!

Close up on chicken and spinach egg casserole.

After making my Chicken and Spinach Egg Cups, I thought it would be brilliant to employ the same concept but in casserole form.

What we have here is a powerhouse breakfast with plenty of protein, lots of flavor from the onion, sun-dried tomatoes, and feta, and a boost of micronutrients from a generous amount of spinach.

The end result is a healthy breakfast that comes together so easily!

This easy recipe is perfect for using up lots of leftover chicken. I used leftover chicken from my Crock Pot Whole Chicken, which I had prepared earlier in the week. 

You can also use rotisserie chicken, grilled chicken, or any cooked chicken you have on hand.

This easy breakfast recipe is also a great catchall for any produce you have lingering in the refrigerator that needs to be used up.

Feel free to mix it up using all sorts of additions, such as zucchini, broccoli, sweet potato, green onion, green beans, bell pepper, artichoke hearts, cauliflower, etc.

Chicken and spinach egg casserole fresh out of the oven, ready to serve.

Let’s discuss the simple ingredients for this Chicken Breakfast Casserole.

Ingredients for Chicken and Spinach Breakfast Casserole:

Chicken: Use leftover chicken of any kind for this high-protein breakfast. Simply chop up cooked chicken breasts, thighs, or shred up some rotisserie chicken to toss in.

I use 4 cups, which give me 35 grams of protein per serving when combined with the rest of the ingredients.

Fresh Spinach: Fresh baby spinach adds an infusion of micronutrients and iron. Toss in any additional fresh vegetables you like!

Yellow Onion: Onion gets sauteed up in olive oil or avocado oil to add beautiful fresh flavor to the egg casserole. You can even caramelize the onion for even more flavor.

Fresh Garlic: Finely chop some fresh garlic cloves for a yummy burst of flavor.

Sun-Dried Tomatoes: Sweet, tangy, sun-dried tomatoes are always a win in any egg dish in my humble opinion. If you prefer fresh cherry tomatoes, feel free to replace the sun-dried with 1 cup of fresh.

Feta Cheese: That creamy, tangy feta cheese makes this egg bake such a treat. Feel free to use one cup of any type of grated cheese you like, such as cheddar cheese, jack cheese, Monterey jack, mozzarella cheese, parmesan cheese, etc.

Sea Salt: Add salt to your personal taste here. Black pepper is marvelous too!

Optional Additions:

  • Add in 1 cup of fresh herbs such as chopped fresh basil or fresh parsley.
  • If you love artichoke hearts, feel free to add a jar to the mix.
  • Kalamata olives are dreamy in egg casseroles and add a Mediterranean vibe. Mix in ½ cup to ¾ cup of pitted olives.
  • For a little spunk and spice, add in up to 1 cup of drained pepperoncinis. 
  • Add a kick by mixing in 1/4 to 1/2 teaspoon of red pepper flakes.
  • You can replace the fresh garlic with 2 teaspoons of garlic powder.
  • Replace the chicken with one pound of chicken sausage or turkey sausage if you’d like.
  • Use your favorite leafy greens like kale or chard in place of spinach.

Nutrition Information:

When slicing the casserole into 8 equal sized slices, each hunk contains 350 calories, 7 net carbs, and 35 grams of protein.

For the complete macronutrient breakdown, see the nutrition facts in the recipe card below!

two white plates with slices of egg casserole, ready to eat.

Now that we’re familiar with the healthy ingredients and nutrition facts, let’s bake this healthy casserole recipe!

How to Make Chicken and Spinach Breakfast Casserole:

Preheat the oven to 375 degrees Fahrenheit and spray a large 13” x 9” casserole dish with cooking spray.

Heat the avocado oil in a large skillet over medium-high heat. Add the chopped onion and sauté, stirring occasionally, until the onion begins to soften, about 5 to 8 minutes.

Add in the garlic and baby spinach and cover the skillet until the spinach has wilted, about 2 minutes.

Stir in the sun-dried tomatoes and sprinkle everything with sea salt. Remove from the heat.

Skillet with onion, spinach, sun-dried tomatoes, chicken and garlic.

Transfer the chicken and veggie mixture to the prepared casserole dish and spread everything into an even layer.

Large casserole dish with chicken and vegetables inside.

In a large bowl, whisk together the eggs and egg whites until well-combined. You can season the eggs with salt (which is what I do), depending on your personal taste.

Eggs and egg whites whisked together in a red mixing bowl.

Pour the egg mixture evenly over the chicken and veggies. 

Casserole dish with chicken, vegetables and raw eggs for egg bake.

Stir in the feta cheese, moving everything around to ensure the ingredients are well-distributed throughout the casserole. If you’d like, you can sprinkle any type of grated cheese on top of the casserole.

Feta cheese stirred into raw eggs, vegetables and chicken in a casserole dish, ready to bake.

Bake on the center rack of the preheated oven for 35 to 45 minutes or until the casserole is golden brown on top and tests clean.

If you’d like, you can insert a meat thermometer into the center of the egg casserole to be sure it is fully cooked. It is considered fully cooked once it reaches an internal temperature of at least 190 degrees Fahrenheit. For me, this takes 35 minutes of baking time.

Allow the casserole to cool for at least 10 minutes before slicing and serving.

If you’d like, you can serve the individual slices with toppings such as sour cream, plain Greek yogurt, guacamole, or serve with fresh fruit and toasted bread or a green salad for a complete meal.

Two slices of egg casserole on white plates with the casserole dish of casserole to the side.

The breakfast casserole is even more flavorful the next day! If you’re able to make it in advance, I’d recommend it.

Store any leftovers in an airtight container in the refrigerator for up to 1 week.

The way I see it, this delicious chicken and spinach breakfast casserole is lovely for serving guests for brunch. It is also a great recipe for meal prep.

I like making egg casseroles like this for meal prep so that I have them on hand to just pop in the microwave for a minute whenever breakfast time rolls around. It also makes for a lovely dinner for busy weeknights.

Slices of breakfast casserole on white plates with forks, ready to eat.

If you love easy recipes for breakfast casseroles like this, also try some of these reader favorites!

More Healthy Breakfast Casseroles:

Make it for brunch on repeat!

Close up on chicken and spinach egg casserole.
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4.50 from 8 votes

Chicken and Spinach Breakfast Casserole

A delicious high-protein breakfast that is perfect for sharing for breakfast. Also a great meal prep recipe for a grab and go meal!
Prep Time15 minutes
Cook Time35 minutes
Total Time50 minutes
Course: Breakfast
Cuisine: American
Servings: 8 Servings
Calories: 350kcal
Author: Julia

Ingredients

  • 1 Tbsp avocado oil
  • 1 yellow onion chopped
  • 4 cloves garlic minced
  • 5 ounces baby spinach
  • 6 ounces sun-dried tomatoes drained
  • 4 cups cooked chicken chopped
  • 6 large eggs
  • 1 16-oz carton egg whites
  • 6 ounces feta cheese
  • 1 tsp sea salt to taste

Instructions

  • Preheat the oven to 375 degrees Fahrenheit and spray a large 13” x 9” casserole dish with cooking spray.
  • Heat the avocado oil in a large skillet over medium-high heat. Add the chopped onion and sauté, stirring occasionally, until the onion begins to soften, about 5 to 8 minutes. Add in the garlic and baby spinach and cover the skillet until the spinach has wilted, about 2 minutes. Stir in the sun-dried tomatoes and sprinkle everything with sea salt. Remove from the heat.
    Skillet with onion, spinach, sun-dried tomatoes, chicken and garlic.
  • Transfer the chicken and veggie mixture to the prepared casserole dish and spread everything into an even layer.
    Large casserole dish with chicken and vegetables inside.
  • In a large bowl, whisk together the eggs and egg whites until well-combined. You can season the eggs with salt (which is what I do), depending on your personal taste.
    Eggs and egg whites whisked together in a red mixing bowl.
  • Pour the egg mixture evenly over the chicken and veggies. 
    Casserole dish with chicken, vegetables and raw eggs for egg bake.
  • Stir in the feta cheese, moving everything around to ensure the ingredients are well-distributed throughout the casserole. If you'd like, you can sprinkle any type of grated cheese on top of the casserole.
    Feta cheese stirred into raw eggs, vegetables and chicken in a casserole dish, ready to bake.
  • Bake on the center rack of the preheated oven for 35 to 45 minutes or until the casserole is golden brown on top and tests clean.
  • If you’d like, you can insert a meat thermometer into the center of the egg casserole to be sure it is fully cooked. It is considered fully cooked once it reaches an internal temperature of at least 190 degrees Fahrenheit. For me, this takes 35 minutes of baking time.
  • Allow the casserole to cool for at least 10 minutes before slicing and serving.
  • If you’d like, you can serve the individual slices with toppings such as sour cream, plain Greek yogurt, guacamole, or serve with fresh fruit and toasted bread or a green salad for a complete meal.

Notes

The breakfast casserole is even more flavorful the next day! If you're able to make it in advance, I'd recommend it.

Nutrition

Serving: 1Slice (of 8) | Calories: 350kcal | Carbohydrates: 8g | Protein: 35g | Fat: 20g | Saturated Fat: 7g | Polyunsaturated Fat: 7g | Cholesterol: 220mg | Sodium: 473mg | Fiber: 1g | Sugar: 3g

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Recipe Rating




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Lee

Monday 15th of May 2023

Can you substitute more whole eggs for the carton of egg whites?

Lee

Wednesday 31st of May 2023

@Julia, I tried this recipe with the carton of egg whites and it was great! Next time I’ll try with all whole eggs. Thanks for this yummy recipe!

Julia

Friday 19th of May 2023

Hi Lee! Absolutely! I would use 6 whole eggs instead of the egg whites. Hope you enjoy!

Theresa

Wednesday 3rd of May 2023

What cheese could be used to replace feta?

Julia

Monday 8th of May 2023

Hi Theresa! Anything you like will work! Grated cheddar, jack cheese, colby jack cheese, and goat cheese are all great options :)

Donna

Thursday 6th of April 2023

Can I halve the recipe and omit the egg whites for a smaller casserole?

Julia

Thursday 6th of April 2023

Hi Donna! I'm betting that would work great! You may want to adjust the bake time down a little, but aside from that I bet it will turn out deliciously! xo

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